Pretreatment method of premature peach hybrid seeds and application of premature peach hybrid seeds in direct sowing and seedling raising

Abstract

The invention provides an early-maturing peach hybrid seed pretreatment method and application thereof in direct sowing and seedling raising, and belongs to the technical field of plant breeding. The invention provides a pretreatment method of early-maturing peach hybrid seeds, which comprises the following steps: disinfecting completely-matured early-maturing peach hybrid fruits, taking out seed kernels, mixing the seed kernels with a culture solution, carrying out ultrasonic treatment, and drying in the shade. By utilizing the pretreatment method disclosed by the invention, the seeds which cannot completely develop embryos due to the short development period of fruits, finally have no direct seeding breeding prospect and even are not suitable for embryo rescue can be subjected to multiple stimulation by multiple nutrient substances and plant growth regulators in the culture solution under the microwave condition, so that the seeds can be fully cultured. The seed kernels continue to grow and develop after being in vitro, and the wizened or gelatinous seeds without embryo culture are subjected to in-vitro development and after-ripening. According to the seeds treated through the pretreatment method, dormancy is almost broken, the low-temperature stratification time can be shortened, and even direct seeding breeding can be achieved without low-temperature stratification treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of plant breeding, and particularly relates to a pretreatment method for early-maturing peach hybrid seeds and an application of the pretreatment method in direct sowing and seedling raising. Background Art

[0002] In the process of peach breeding, especially in the hybrid breeding of early-maturing peach and very early-maturing peach, due to the influence of various factors, the success rate of peach hybrid pollination and the success rate of early-maturing peach embryo culture are far from 100%, so the seed treatment seedling rate is particularly important in the later stage.

[0003] Using early-maturing or very early-maturing peach varieties as parents and using embryo culture technology is a common breeding method for early-maturing peaches. However, the fruit development period of very early-maturing or early-maturing peach varieties is often short, and abortion often occurs in the early stages of embryo development, making it very difficult to obtain offspring through normal methods. Therefore, embryo abortion is a key issue that restricts fruit tree hybrid breeding.

[0004] At present, in the method of overcoming embryo abortion, the culture method is mostly to transfer the embryo into the culture medium before the young embryo is aborted, and cultivate the embryo to survive under artificial conditions. In the embryo culture technology of peach, the embryo age directly affects the seedling rate and the growth potential of the seedling. Early studies believed that the embryo development index (PF value, embryo length / seed length) close to 0.7 is the minimum value for successful peach embryo culture. Later experiments found that only when the young embryo with a development index greater than 0.2 is transferred to normal temperature culture, the cotyledons can grow rapidly and turn green, and eventually it may be cultivated into seedlings; while the young embryo with a development index less than 0.2 will no longer develop, will not turn green, and cannot be cultivated into seedlings. It is generally believed that the younger the embryo age, the more difficult it is to cultivate, and the older the embryo age, the greater the possibility of embryo atrophy and degeneration. Therefore, it is still difficult to cultivate very early or early peaches by embryo rescue.

[0005] The germination ability of peach embryos is generally positively correlated with their size. For peaches with a fruit growth period of less than 90 to 100 days, due to the short growth time and incomplete embryo development, the seeds cannot germinate or have a very low germination rate under conventional sowing conditions. Early-maturing peach seeds with a fruit development period of less than 75 days are generally difficult to germinate because the embryos are too small. Plant embryo rescue is to remove the embryos that are about to abort from the ovary or ovule. However, under some conditions, it is technically impossible to remove the embryos. Therefore, if you want to rescue these embryos, you must culture the entire ovary or ovule. In general, in the existing breeding technologies for preventing peach embryo abortion, there are generally problems such as difficulty in technical implementation, cumbersome culture steps and high economic costs. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a pretreatment method for early-maturing peach hybrid seeds and its application in direct sowing and seedling raising. After the hybrid seeds of early-maturing peach or even very early-maturing peach are treated by the method, the gelatinous seeds can be stimulated to grow and mature in vitro, and dormancy can be broken in a short time for direct sowing and breeding.

[0007] The present invention provides a method for pre-treating early-maturing peach hybrid seeds, comprising the following steps: (1) after hybrid pollination of early-maturing peach varieties, picking fully mature fruits, disinfecting the fruits, breaking the cores and taking out the seed kernels; (2) Mix the seed kernels with the culture medium, treat with ultrasound for 20 to 50 hours, and then dry in the shade; The culture solution uses WPM culture medium as the basic culture medium and further comprises components with the following concentrations: 0.03-0.2 mg / L melatonin, 0.02-0.08 mg / L NAA, 4-12 g / L tomato juice, 1-6 g / L banana juice, 7-12 g / L seaweed powder and 15-30 g / L sucrose.

[0008] In a preferred embodiment of the present invention, the fruit disinfection in step (1) comprises soaking in an alcohol aqueous solution with a volume percentage of 65-75% and soaking in a sodium hypochlorite aqueous solution with a volume percentage of 3-5%.

[0009] In a preferred embodiment of the present invention, the alcohol aqueous solution is immersed for 5 to 10 minutes; The immersion time of the sodium hypochlorite aqueous solution is 10 to 20 minutes.

[0010] In a preferred embodiment of the present invention, the volume ratio of the seed kernels to the culture medium in step (2) is 10 to 20 seed kernels / 100 mL of culture medium.

[0011] In a preferred embodiment of the present invention, the culture solution uses WPM culture medium as the basic culture medium and further includes the following components in concentrations: melatonin 0.05-0.15 mg / L, NAA 0.04-0.06 mg / L, tomato juice 7-10 g / L, banana juice 3-5 g / L, seaweed powder 8-10 g / L and sucrose 18-25 g / L.

[0012] In a preferred embodiment of the present invention, the temperature of the ultrasonic treatment in step (2) is 25-30°C, the ultrasonic frequency is 15-100 kHz, the power is 200 W, and during the ultrasonic treatment, the ultrasonic treatment is performed for 3 seconds with a rest period of 2 seconds.

[0013] In a preferred embodiment of the present invention, the temperature of the shade drying in step (2) is 2-10° C. and the time is not less than 5 days.

[0014] The present invention also provides application of the pretreatment method in direct seeding and raising hybrid peach seedlings.

[0015] The present invention also provides a method for direct seeding breeding of early-maturing peaches, comprising sowing the seeds treated by the pretreatment method in a matrix.

[0016] In a preferred embodiment of the present invention, the raw materials for preparing the matrix include vermiculite, peat soil, aloe vera gel, plant straw and livestock and poultry manure.

[0017] In a preferred embodiment of the present invention, the invention further comprises, after the sowing, alternately watering with clean water and diluted culture solution; The culture solution uses WPM culture medium as the basic culture medium and further comprises components with the following concentrations: 0.03-0.2 mg / L melatonin, 0.02-0.08 mg / L NAA, 4-12 g / L tomato juice, 1-6 g / L banana juice, 7-12 g / L seaweed powder and 15-30 g / L sucrose.

[0018] Beneficial effects: The present invention provides a pretreatment method for early-maturing hybrid peach seeds, wherein the seed kernels are taken out after disinfection of fully mature hybrid fruits, and the seed kernels are mixed with culture solution and then ultrasonically treated, and then dried in the shade. By using the pretreatment method of the present invention, seeds that cannot fully develop embryos due to a short fruit development period and ultimately have no prospect for direct seeding breeding or are even unsuitable for embryo rescue can be subjected to multiple stimulations with a variety of nutrients and plant growth regulators in the culture solution under microwave conditions, so that the seed kernels continue to grow and develop after being separated from the body, and the seeds that are shriveled or gelatinous and do not have embryo culture complete in vitro development and ripening. The seeds treated by the pretreatment method of the present invention have almost broken dormancy, and the low-temperature stratification time can be shortened or even direct seeding breeding can be performed without low-temperature stratification treatment. According to statistics, after the pretreatment, the extremely early hybrid seeds can obtain a direct seeding germination rate of more than 50% and a seedling rate of 83% after stratification treatment in an environment of 2-10°C for 12-20 days; after the pretreatment, the early hybrid seeds can be directly seeded for germination without stratification treatment, and the germination rate is as high as 64% and the seedling rate can reach 86%; and after the pretreatment, the germination rate of the early and extremely early hybrid seeds is about 45% without low-temperature stratification treatment, and when the low-temperature stratification treatment is performed for more than 5 days, within 20 days, as the low-temperature stratification treatment time is prolonged, the germination rate is also improved, and the highest can reach about 68%. By utilizing the pretreatment method of the present invention, early-maturing / early-maturing, very early-maturing / very early-maturing, and early-maturing / very early-maturing hybrid seeds that do not have the ability to culture embryos can complete after-ripening in vitro and basically break dormancy, and can achieve a higher germination rate and shorten the breeding time by undergoing a short-term low-temperature layer treatment or without undergoing a low-temperature layer treatment. DETAILED DESCRIPTION

[0019] The present invention provides a method for pretreating early-maturing peach hybrid seeds, comprising the following steps: (1) picking fully mature fruits after hybrid pollination of early-maturing peach varieties, sterilizing the fruits, breaking the cores and taking out the seed kernels; (2) Mix the seed kernels with the culture medium, treat with ultrasound for 20 to 50 hours, and then dry in the shade; The culture solution uses WPM culture medium as the basic culture medium and further comprises components with the following concentrations: 0.03-0.2 mg / L melatonin, 0.02-0.08 mg / L NAA, 4-12 g / L tomato juice, 1-6 g / L banana juice, 7-12 g / L seaweed powder and 15-30 g / L sucrose.

[0020] The early-ripening peaches referred to in the present invention are based on the fruit growth period in Sichuan Province, and peaches with a fruit growth period of 80 to 85 days are called early-ripening peaches, and peaches with a growth period of 65 to 75 days in early-ripening peaches are called very early-ripening peaches. For example, in the present invention, peach varieties of very early-ripening peaches include Huaguang (fruit growth period 65 to 70 days), special early Micui peach 5-19 (ripening around May 19, fruit growth period 50 to 55 days), early-ripening Wuming peach (ripening around May 17, fruit growth period 47 to 55 days), special early Hongcuiwang (fruit growth period around 50 days), extremely early 520 Hongcui peach (ripening around May 20) and Chunli peach (fruit growth period around 65 days), as well as Zhongtao Hongyu (fruit growth period around 75 days), Zhongtao Ziyu (fruit growth period 65 to 70 days) and Yanzhicui peach (fruit growth period 65 to 70 days), etc. The early-maturing peach varieties of the present invention include Jinchun (fruit growing period is 78-82 days), Zhongtao 9 (fruit growing period is about 80 days), Huangyu 1 (fruit growing period is about 85 days) and Zhongyoupan 9 (fruit growing period is about 85 days).

[0021] The present invention adopts the following combinations to hybridize peach varieties: early maturing / early maturing, very early maturing / very early maturing and early maturing / very early maturing, to verify the effectiveness of the pretreatment method of the present invention. The present invention does not specifically limit the hybridization method. For example, in the embodiment, cross-pollination hybridization is performed on each variety in the large bud stage, and the tassels are emasculated by the continuous emasculation method, and the tassels are marked after artificial pollination. The continuous emasculation method can be performed with reference to the article of Chen Xuesen et al. (Chen Xuesen, Zhang Yanmin. Breeding of very early-maturing apricot [J]. Acta Horticulturae Sinica, 1996, 23 (1): 27.31.).

[0022] After the hybrid fruit is obtained, the hybrid fruit can be picked when it reaches full maturity, and the picked fruit is sterilized as a whole, wherein the sterilization comprises soaking in alcohol aqueous solution and sodium hypochlorite aqueous solution in sequence, wherein the volume percentage of the alcohol aqueous solution is 65-75%, such as 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74% and 75%, and the soaking time can be 5-10 minutes, such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes and 10 minutes. Then, after taking out the hybrid fruit from the alcohol aqueous solution, soak it in sodium hypochlorite aqueous solution, wherein the concentration of the sodium hypochlorite aqueous solution can be 3-5%, such as 3%, 4% and 5%, and the soaking time is 10-20 minutes, such as 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes and 20 minutes. In one embodiment of the present invention, after soaking in a 72% alcohol aqueous solution for 8 minutes, the sample is transferred to a 5% sodium hypochlorite aqueous solution and soaked for 15 minutes.

[0023] The present invention places the fruit taken out from the sodium hypochlorite aqueous solution in a sterile environment, such as the clean bench used in the embodiment, removes the pulp, uses sterilized scissors to break the core of the fruit to take out the seeds, and inoculates the seed kernels into the culture solution. The quantity volume ratio of the seed kernels and the culture solution of the present invention is 10 to 20 seed kernels / 100 mL of culture solution. The culture solution of the present invention uses WPM culture medium as the basic culture medium, and various effective ingredients such as melatonin, NAA, tomato juice, banana juice, seaweed powder and sucrose are added to the basic culture medium.

[0024] The concentration of melatonin in the culture solution of the present invention is 0.03-0.2 mg / L, such as 0.05-0.15 mg / L, specifically 0.05 mg / L, 0.06 mg / L, 0.07 mg / L, 0.08 mg / L, 0.09 mg / L, 0.10 mg / L, 0.11 mg / L, 0.12 mg / L, 0.13 mg / L, 0.14 mg / L and 0.15 mg / L. The melatonin of the present invention can stimulate seed reproduction in vitro and stimulate germination.

[0025] The concentration of NAA in the culture solution of the present invention is 0.02-0.08 mg / L, such as 0.02 mg / L, 0.03 mg / L, 0.04 mg / L, 0.05 mg / L, 0.06 mg / L, 0.07 mg / L and 0.08 mg / L. The NAA of the present invention can promote seed germination.

[0026] The culture solution of the present invention contains tomato juice, and the concentration of the tomato juice is 4-12g / L, such as 4g / L, 5g / L, 6g / L, 7g / L, 8g / L, 9g / L, 10g / L, 11g / L and 12g / L. The present invention does not specifically limit the source of the tomato juice, and the purchased tomatoes can be directly squeezed for juice. When squeezing the juice, the mixing ratio of tomato and water is 100g:20g, and then directly added to the culture solution. The tomato juice of the present invention contains a large amount of saponin components, such as steroidal saponins, tomato saponin A, tomato saponin B and tomato saponin C, etc., a large amount of vitamin C and other active ingredients, which can provide an acidic environment and inhibit the rot of seeds.

[0027] The culture solution of the present invention contains banana juice, and the concentration of the banana juice is 1-6 g / L, such as 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L and 6 g / L. The present invention does not specifically limit the source of the banana juice, and the banana can be peeled and then squeezed with water. For example, in the embodiment, the peeled banana and water are mixed in a ratio of 100 g:40 g and then squeezed, and the juice is directly added to the culture solution. The banana juice of the present invention contains a high amount of potassium, as well as a large amount of phenolic compounds, catecholamines and colorless anthocyanins, which can stimulate gelatinous immature seeds to complete after-ripening and continue to grow and differentiate in vitro.

[0028] The culture solution of the present invention contains seaweed powder, and the concentration of the seaweed powder is 7-12 g / L, such as 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L and 12 g / L. The seaweed powder of the present invention contains a large amount of polysaccharides, proteins, minerals (calcium, iron, sodium, phosphorus, magnesium and iodine, etc.), vitamins, cellulose, polyphenol compounds, seaweed glycoproteins, etc., has good antioxidant effect, can promote the exchange of contents between the culture solution and seeds, and enhance the continued growth ability of seeds.

[0029] The present invention does not specifically limit the preparation method of the culture solution. For example, after mixing the above components, the volume is fixed with sterile water, and then sterilized, and the peeled seed kernels can be mixed with the culture solution after cooling. The quantity volume ratio of the seed kernels and the culture solution of the present invention is 10 to 20 grains / 100mL, such as 10 grains / 100mL, 11 grains / 100mL, 12 grains / 100mL, 13 grains / 100mL, 14 grains / 100mL, 15 grains / 100mL, 16 grains / 100mL, 17 grains / 100mL, 18 grains / 100mL, 19 grains / 100mL and 20 grains / 100mL. In one embodiment of the present invention, 15 seed kernels are placed in every 100mL of the culture solution. Then they are placed together in an ultrasonic treatment device for ultrasonic treatment, and the temperature of the ultrasonic treatment is 25-30°C, such as 25°C, 26°C, 27°C, 28°C, 29°C and 30°C. For example, in one embodiment of the present invention, the temperature is controlled at 27-30°C. The frequency of the ultrasonic treatment of the present invention can be 15-100kHz, such as 28-59kHz. In one embodiment, a frequency of 40kHz is selected for the ultrasonic treatment. The power of the ultrasonic treatment is controlled to be 200W, and during the ultrasonic treatment, the ultrasonic treatment is performed for 2s every 3s. Using the parameters of the present invention, it is necessary to perform ultrasound for 20-50h, which can be 25-40h, such as 25h, 26h, 27h, 28h, 29h, 30h, 31h, 32h, 33h, 34h, 35h, 36h, 37h, 38h, 39h and 40h.

[0030] The present invention utilizes ultrasound combined with culture fluid to stimulate the in vitro seed kernel to absorb the active ingredients in the culture fluid and complete seed ripening; and because of the addition of tomato juice and banana juice, a large amount of culture fluid can be adsorbed on the surface of the seed kernel during the ultrasonic treatment process, providing artificial endosperm and seed coat for subsequent seed growth.

[0031] After the ultrasonic treatment, the present invention performs shade drying, which can be performed under breeze conditions, such as natural air circulation, and the shade drying temperature is controlled to be 2-10°C for a period of not less than 5 days. The shade drying process of the present invention is similar to the low temperature stratification dormancy breaking process, and after the shade drying, most of the hybrid seeds can be used for direct seeding breeding.

[0032] In summary, the present invention also provides the application of the above-mentioned pretreatment method in direct seeding of hybrid peach seedlings.

[0033] The present invention also provides a method for direct seeding breeding of early-maturing peaches, comprising sowing the seeds treated by the pretreatment method in a matrix.

[0034] After the pretreatment of the present invention, the very early-maturing hybrid seeds can obtain a direct-seeding germination rate of more than 50% and a seedling rate of 83% after stratification treatment for 12 to 20 days in an environment of 2 to 10°C after the pretreatment; the early-maturing hybrid seeds can be directly seeded for germination without stratification treatment after the pretreatment, and the germination rate is as high as 64% and the seedling rate can reach 86%; and the early-maturing and very early-maturing hybrid seeds can also have a germination rate of about 45% without low-temperature stratification treatment after the pretreatment, and when the low-temperature stratification treatment is carried out for more than 5 days, within 20 days, as the time of low-temperature stratification treatment is prolonged, the germination rate is also improved, and can reach up to about 68%.

[0035] In the direct seeding breeding of the present invention, it is necessary to sow the seeds that have been pretreated and / or stratified after pretreatment into a matrix, and the raw materials for preparing the matrix include vermiculite, peat soil, aloe gel, plant straw and livestock and poultry manure, and the mass ratio of the vermiculite, peat soil, aloe gel, plant straw and livestock and poultry manure is 1:3:(2-6):(18-46):(25-67), such as 1:3:3:25:50, 1:3:5:32:30, 1:3:2:45:63 or 1:3:6:35:55. After mixing according to the ratio, the mixed material is sealed and fermented for more than 20 days until the fermentation pile temperature is stably lower than 45°C, and the fermentation is terminated, and the seeds can be sown after drying to a moisture content of about 7%.

[0036] The present invention also needs to be irrigated after the sowing. When irrigating, the first time is to irrigate until the water content reaches more than 90%, and then irrigate when the soil moisture content is less than 50%. At this time, the irrigating is carried out using the dilution of the culture solution, and the soil moisture content reaches about 80%. When the soil moisture content is dried again and is less than 50%, it is irrigated with clean water until the soil moisture content reaches 90%, and then alternately irrigated with clean water and the dilution of the culture solution. The dilution of the present invention can be a 10-fold dilution of the culture solution.

[0037] In order to further illustrate the present invention, a method for pretreating early-maturing peach hybrid seeds provided by the present invention and its application in direct sowing and seedling raising are described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0038] Example 1 The very early-maturing peach varieties and the early-maturing varieties were hybridized separately.

[0039] (1) During the flowering period, the female and male parents are artificially emasculated and pollinated for hybridization. After pollination, the fruits are harvested when they are fully ripe. The fruit disinfection method is to first immerse the fruit in 72% alcohol for 8 minutes, and then immerse the fruit in 5% sodium hypochlorite aqueous solution for 15 minutes. The fruit will be broken with sterilized scissors on a clean bench to remove the seeds; (2) Mix WPM medium with melatonin, NAA, tomato juice, banana juice, seaweed powder and sucrose, dissolve and adjust the volume with sterile water, then sterilize at high temperature and cool to room temperature.

[0040] The culture medium composition: WPM, melatonin 0.1 mg / L, NAA 0.05 mg / L, tomato juice 8.5 g / L, banana juice 4 g / L, seaweed powder 8.5 g / L and sucrose 20 g / L.

[0041] (3) Add 15 seed kernels to every 100 mL of culture medium and control the temperature between 27 and 30 °C. Set the ultrasonic frequency to 40 kHz and the power to 200 W. Ultrasonicate for 3 seconds with a 2-second break for a total of 40 hours.

[0042] (4) After ultrasound, take out the seeds and place them in the shade to dry indoors for 5 days.

[0043] (5) The shade-dried seeds were randomly divided into 6 groups, with 100 seeds in each group: Group 1: sowing after 5 days of low temperature storage at 4℃; Group 2: sowing after 10 days of low temperature storage at 4℃; Group 3: sowing after 15 days of low temperature storage at 4℃; Group 4: sowing after 20 days of low temperature storage at 4℃; Group 5: sowing after 30 days of low temperature storage at 4℃; Group 6: Direct sowing.

[0044] The matrix used for sowing consists of raw materials of vermiculite, peat soil, aloe vera gel, plant straw and livestock and poultry manure in a mass ratio of 1:3:3:25:50.

[0045] The irrigation mode is: alternating irrigation with clean water and 10-fold diluted culture solution.

[0046] One month after sowing, the germination rate results are shown in Table 1. For the seeds of the combination of Zhongtao Hongyu (female parent) / Rouge Crisp Peach (male parent), no germination was observed in the first and sixth groups, only 7 seeds germinated in the second group, 38 seeds germinated in the third group, 52 seeds germinated in the fourth group, and 43 of them grew into seedlings with well-developed root systems; 53 seeds germinated in the fifth group, and 41 of them grew into seedlings; although the germination rate of the fifth group was higher than that of the fourth group, the improvement was not large, and the seedling rate was reduced.

[0047] At the same time, for the seeds of the combination of Zhongtao No. 9 (female parent) / Huangyu No. 1 (male parent), 64 seeds germinated in the sixth group, and 55 of them matured into seedlings with well-developed root systems; 64 seeds germinated in the first group, 57 seeds germinated in the second group, and only 26, 19 and 8 seeds were sown in the third to fifth groups respectively.

[0048] Moreover, for the seeds of the Zhongtao Ziyu (female parent) / Jinchun (male parent) combination, 45 seeds germinated in the sixth group, 47 seeds germinated in the first group, 52 seeds germinated in the second group, 61 seeds germinated in the third group, 68 seeds germinated in the fourth group, and 63 seeds germinated in the fifth group.

[0049] Table 1 Statistics of germination rate

[0050] Comparative Example 1 The combination of Zhongtao No. 9 (female parent) and Huangyu No. 1 (male parent) in Example 1 was used, and except for the different composition of the culture solution from Example 1, the rest of the operations were exactly the same as those of the sixth group of experiments in Example 1 to evaluate the effect of the culture solution. 100 seeds were set for each treatment group: Treatment group 1: culture medium composition: WPM, NAA 0.05 mg / L, tomato juice 8.5 g / L, banana juice 4 g / L, seaweed powder 8.5 g / L and sucrose 20 g / L; Treatment group 2: culture medium composition: WPM, melatonin 0.1 mg / L, tomato juice 8.5 g / L, banana juice 4 g / L, seaweed powder 8.5 g / L and sucrose 20 g / L; Treatment group 3: culture medium composition: WPM, melatonin 0.1 mg / L, NAA 0.05 mg / L, banana juice 4 g / L, seaweed powder 8.5 g / L, and sucrose 20 g / L; Treatment group 4: culture medium composition: WPM, melatonin 0.1 mg / L, NAA 0.05 mg / L, tomato juice 8.5 g / L, seaweed powder 8.5 g / L and sucrose 20 g / L; Treatment group 5: culture medium composition: WPM, melatonin 0.1 mg / L, NAA 0.05 mg / L, tomato juice 8.5 g / L, banana juice 4 g / L and sucrose 20 g / L; Treatment group 6: culture medium composition: WPM, tomato juice 8.5 g / L, banana juice 4 g / L, seaweed powder 8.5 g / L and sucrose 20 g / L; Treatment group 7: culture medium composition: WPM, melatonin 0.1 mg / L, NAA 0.05 mg / L, seaweed powder 8.5 g / L, and sucrose 20 g / L; Treatment group 8: culture medium composition: WPM, melatonin 0.1 mg / L, NAA 0.05 mg / L, and sucrose 20 g / L; Treatment group 9: culture medium composition: MS, melatonin 0.1 mg / L, NAA 0.05 mg / L, tomato juice 8.5 g / L, banana juice 4 g / L, seaweed powder 8.5 g / L and sucrose 20 g / L; Treatment group 10: culture medium composition: WPM.

[0051] After sowing for one month, the germination rate of the seeds of the combination of Zhongtao No. 9 (female parent) / Huangyu No. 1 (male parent) is shown in Table 2. Although the germination rate data of treatment group 1, treatment group 2 and the sixth group of Example 1 are similar, the seedling rate is less than half of the sixth group, which proves that melatonin and NAA have a significant effect on the seedling rate; other treatment groups such as treatment groups 3 to 7 and treatment group 9 can germinate, but the leaves turn yellow after germination, the root amount is very small, and the seedling rate is low; only one seed germinates in treatment group 8, but it fails to seed; treatment group 10 cannot germinate, that is, tomato juice, banana juice, seaweed powder and sucrose are mainly used to provide the energy required for germination and provide a germination environment, and under the state of nutritional imbalance, even if it contains melatonin and NAA that are conducive to seedling formation, the seedling rate is also very low. It is proved that the components of the culture solution of the present invention are all necessary, and the lack of any component greatly affects the germination rate and seedling rate of seeds. It is speculated that the components of the culture solution have a synergistic effect, and the lack of any component leads to the disappearance of the synergistic effect, thereby significantly reducing the germination rate and seedling rate.

[0052] Table 2 Germination rate and seedling rate of Zhongtao 9 / Huangyu 1 combination in different treatment groups

[0053] Comparative Example 2 The combination of Zhongtao No. 9 (female parent) / Huangyu No. 1 (male parent) in Example 1 was used, and except for the ultrasonic treatment which was different from the sixth group in Example 1, the rest of the operations were exactly the same as the sixth group, and 50 seeds were processed in each treatment group: Treatment group 1: 27-30℃, 40kHz, 200W, 3s ultrasonic wave and 2s rest, for a total of 10h ultrasonic treatment; Treatment group 2: 37-40°C, 40kHz, 200W, 3s ultrasonic wave and 2s rest, for a total of 40h; Treatment group 3: 27-30°C, 140kHz, 200W, 3s ultrasonic wave and 2s rest, for a total of 10h Treatment group 4: 27-30℃, 10kHz, 200W, 3s ultrasonic wave and 2s rest, for a total of 30h ultrasonic treatment; Treatment group 5: 27-30℃, 10kHz, 50W, ultrasonic treatment for 2s each time and 2s rest, for a total of 30h.

[0054] One month after sowing, the seed germination statistics of the Zhongtao 9 (female parent) / Huangyu 1 (male parent) combination are shown in Table 3. The number of seeds germinated in treatment groups 1 to 5 were 0, 1, 1, 1 and 0, respectively.

[0055] Table 3 Germination rate of Zhongtao No. 9 / Huangyu No. 1 combination seeds under different ultrasonic operations

[0056] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for pretreating early-maturing peach hybrid seeds, characterized in that: The following steps are involved: (1) After cross-pollination of early-maturing varieties, pick fully mature fruits, disinfect the fruits, and then break the cores to remove the kernels; (2) Mix the seed kernels with the culture medium, treat with ultrasound for 20 to 50 hours, and then dry in the shade; The culture solution uses WPM culture medium as the basic culture medium and further comprises components with the following concentrations: 0.03-0.2 mg / L melatonin, 0.02-0.08 mg / L NAA, 4-12 g / L tomato juice, 1-6 g / L banana juice, 7-12 g / L seaweed powder and 15-30 g / L sucrose.

2. The pretreatment method according to claim 1, characterized in that: The fruit disinfection in step (1) comprises soaking in an alcohol aqueous solution with a volume percentage of 65-75% and soaking in a sodium hypochlorite aqueous solution with a volume percentage of 3-5%.

3. The pretreatment method according to claim 2, characterized in that: The alcohol aqueous solution is immersed for 5 to 10 minutes; The immersion time of the sodium hypochlorite aqueous solution is 10 to 20 minutes.

4. The pretreatment method according to claim 1, characterized in that: The quantity-volume ratio of the seed kernels to the culture medium in step (2) is 10-20 seed kernels / 100 mL of culture medium.

5. The pretreatment method according to claim 4, characterized in that: The culture solution uses WPM culture medium as the basic culture medium and also includes components with the following concentrations: 0.05-0.15 mg / L melatonin, 0.04-0.06 mg / L NAA, 7-10 g / L tomato juice, 3-5 g / L banana juice, 8-10 g / L seaweed powder and 18-25 g / L sucrose.

6. The pretreatment method according to claim 1, characterized in that: The temperature of the ultrasonic treatment in step (2) is 25-30° C., the ultrasonic frequency is 15-100 kHz, the power is 200 W, and during the ultrasonic treatment, the ultrasonic treatment is performed for 3 seconds with a rest period of 2 seconds.

7. Application of the pretreatment method according to any one of claims 1 to 6 in direct seeding of hybrid peach seedlings.

8. A method for direct seeding early-maturing peaches, characterized in that: The method comprises sowing seeds treated by the pretreatment method according to any one of claims 1 to 6 in a matrix.

9. The direct seeding breeding method according to claim 8, characterized in that: The raw materials for preparing the matrix include vermiculite, peat soil, aloe gel, plant straw and livestock and poultry excrement.

10. The direct seeding breeding method according to claim 8, characterized in that: The method further comprises: after the sowing, alternately watering with clean water and a diluted solution of the culture solution; The culture solution uses WPM culture medium as the basic culture medium and further comprises components with the following concentrations: 0.03-0.2 mg / L melatonin, 0.02-0.08 mg / L NAA, 4-12 g / L tomato juice, 1-6 g / L banana juice, 7-12 g / L seaweed powder and 15-30 g / L sucrose.

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