Application of melatonin in seedless induction of grapes

Abstract

The invention discloses application of melatonin in seedless induction of grapes, and belongs to the technical field of seedless grape cultivation. Melatonin is adopted for seedless induction of grapes, complex proportioning is not needed, only one-time dipping is needed, operation is easy and convenient, cost is low, and the method is suitable for popularization. When the melatonin is used in a full-bloom stage, more than 90 days away from a grape ripening and picking stage, the melatonin is fast in metabolism and free of residues and meets the national standard, and the melatonin is an endogenous substance of a human body, is high in safety and is not prone to generating negative effects on the human body; the seedless effect is achieved, and the fruits are good in taste, moderate in sourness and sweetness and full in grain. And a safer and more efficient core-free scheme is provided for technicians in the field.

Description

Technical Field

[0001] This invention relates to the field of seedless grape cultivation technology, and more specifically to the application of melatonin in the induction of seedlessness in grapes. Background Technology

[0002] Seedless grapes are popular among consumers due to their convenience and excellent taste. However, the existing seedless variety resources are limited and cannot meet the diverse needs of consumers. In scientific research on horticultural and agricultural crops, there are three main methods for cultivating seedless grapes: one is to obtain naturally occurring seedless grape varieties through hybridization or transgenic methods; the second is to screen and cultivate grape plants with gene mutations that lead to seed abortion; and the third is to apply plant growth regulators during fruit development to induce seedlessness without affecting the normal growth of the fruit.

[0003] However, the first and second methods mentioned above suffer from problems such as long breeding cycles, high costs, limited variety, insufficient flavor, and unstable seedless trait expression in offspring. Furthermore, the safety of genetically modified organisms remains controversial, restricting their large-scale promotion. While the third method, which uses plant growth regulators to induce seedless grapes, is widely used in production, it often involves the use of drugs and preparations that are prohibited from being added to fruit and vegetable production by the state. For example, streptomycin (SM), also known as agricultural streptomycin sulfate, was once used for seedless treatment, but as a antibiotic fungicide, it has certain toxicity. When applied to vegetables, fruits, and other crops, it poses a risk of bioaccumulation in the food chain and has been completely withdrawn from the market since June 15, 2018.

[0004] Gibberellic acid (GA3) is a commonly used plant growth regulator with various functions in different crops and developmental stages. It can promote fruit enlargement, fruit set, and vegetative seed germination. Taking grapes as an example: spraying gibberellic acid can promote fruit enlargement, promote seedlessness, and increase fruit set. However, in practical applications, gibberellic acid-induced seedlessness often leads to lignification of the fruit stalk, increasing the risk of berry drop, cracking, and rotting. Moreover, if the concentration is inappropriate, it can easily cause hollow fruit, affecting the appearance and quality of the grapes.

[0005] Therefore, developing a novel nucleation agent to overcome the shortcomings of existing technologies and provide a safer and more efficient nucleation solution is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a novel application of melatonin in the induction of seedlessness in grapes, offering a safer and more efficient seedlessness solution.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] Application of melatonin in the preparation of seedless grape formulations.

[0009] Furthermore, the melatonin concentration is 100-200 μM.

[0010] Furthermore, the melatonin concentration is 150 μM.

[0011] Furthermore, the grapes are of the 'Sunshine Rose' variety.

[0012] Another object of the present invention is to provide a method for inducing seedlessness in grapes by soaking the inflorescences in a melatonin solution during the peak flowering period of grapes.

[0013] Furthermore, the soaking time is 4 to 6 seconds.

[0014] Another objective of this invention is to provide a formulation for inducing seedlessness in grapes, the active ingredient of which is melatonin.

[0015] As can be seen from the above technical solution, this invention uses melatonin to induce seedlessness in grapes. It requires no complex formulation, only a single dip, making it simple to operate, low in cost, and suitable for widespread application. When used during peak flowering, more than 90 days before the grape harvest, it metabolizes quickly and leaves no residue, meeting national standards and therefore unlikely to have negative effects on the human body. Furthermore, it achieves seedlessness, resulting in better fruit taste, a balanced sweet and sour flavor, and plump berries. This provides a safer and more efficient seedless solution for those skilled in the art. Attached Figure Description

[0016] Figure 1 Comparison of effects of nucleus-free treatment: CK: blank control (H2O), MT: 150μM melatonin treatment. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] All reagents used in the embodiments of this invention were purchased from commercial channels. Methods not mentioned are conventional experimental methods and will not be described in detail here.

[0019] The following reagents are provided as examples:

[0020] Melatonin (CAS No.: 73-31-4), 25g, purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number M813985-25g.

[0021] Gibberellin (CAS No.: 77-06-5), 100g, purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number G810401-100g.

[0022] Example 1

[0023] In early to mid-May 2024, a seedless treatment experiment was conducted on 5-year-old 'Sunshine Rose' grapevines at the Jinniushan Grape Planting Base in Tai'an City, Shandong Province (117°02′E, 36°13′N). The grapevines were planted using a simple rain-sheltered cultivation method, with rows oriented east-west and a plant spacing of 2m × 4m. To avoid interference from environmental and management differences, all experimental plants underwent uniform fertilizer and water management. Light topping before full bloom and inflorescence shaping pruning were standard procedures in the field. The experiment employed a completely randomized block design, set up according to the treatments shown in Table 1. Grapevines with inflorescences at full bloom were selected, and in the morning or afternoon (avoiding direct sunlight), all shaped inflorescences were immersed in the treatment solution shown in Table 1, with each inflorescence immersed for 4–6 seconds, ensuring uniform contact with the solution (this was done quickly by the same operator to minimize human error). No rainfall was ensured within 24 hours after treatment. Each treatment was replicated in 3 independent blocks, with 10 inflorescences per block.

[0024]

[0025] Fourteen days after the seedless treatment, the flower spikes were dipped in a 25 mg / L gibberellin aqueous solution for 5 seconds to induce fruit enlargement. Harvesting took place in August after maturity. Five mature fruit spikes were randomly selected from each treatment, and ten fruits were taken from the base, middle, and tip of each spike. The seedless rate was calculated (using seedless berries as the standard, only normally mature berries were counted, excluding small seedless berries). Soluble solids (TSS) and total acid (TA) were measured using a handheld sugar-acid analyzer (PAL-BX / ACID F5), and the TSS / TA ratio was calculated. The L*, a, and b values ​​of the equatorial region of the fruit were measured using a spectrophotometer (Konica Minolta CM-2300d), and the color saturation C* was calculated. The results are shown in Table 2.

[0026]

[0027] Table 2 shows that melatonin (MT) treatment exhibits significant advantages in seedlessness rate and fruit quality, specifically as follows:

[0028] (1) Nucleus-free rate: Spraying 150μM MT (T3) alone can achieve 100% nucleation effect, which is significantly better than the control (CK, 3.33%) and GA3 alone (T1, 79%).

[0029] (2) Fruit quality: The TSS of the T3 treatment was the highest (19.71), which was significantly higher than that of the GA3 treatment group (T1, 17.15), indicating that MT can increase the sugar content of grapes; and the TSS / TA of the T3 treatment remained at a high level (32.44), which was better than the control (26.66), indicating that its fruit flavor was better; at the same time, the T3 treatment was close to or better than the GA3 treatment (T1) in terms of brightness (L*=44.35) and color (C*=19.20), indicating that the appearance quality of the fruit was better.

[0030] In summary, treatment of grapes with 150 μM melatonin can achieve seedlessness effects close to or better than GA3, and can further improve fruit sugar content, acid-sugar ratio and appearance quality, demonstrating significant advantages as a novel seedlessness inducer.

[0031] Example 2

[0032] In mid-to-late May 2025, a seedless treatment experiment was conducted on 8-year-old 'Sunshine Rose' grapevines in a vineyard in Wasi Village, Shanghe County, Jinan City, Shandong Province (117°10′E, 37°14′N). The grapevines were cultivated using a simple rain-sheltered system, with rows oriented north-south and a spacing of 2m × 3m between plants. To avoid interference from environmental and management differences, all experimental plants underwent uniform fertilizer and water management. Light topping before full bloom and inflorescence shaping pruning were standard procedures in the field. The experiment employed a completely randomized block design, set up according to the treatments shown in Table 3. Grapevines with inflorescences at full bloom were selected, and in the morning or afternoon (avoiding direct sunlight), all shaped inflorescences were immersed in the treatment solution shown in Table 3, with each inflorescence immersed for 4–6 seconds, ensuring uniform contact with the solution (this was done quickly by the same operator to minimize human error). No rainfall was ensured within 24 hours after treatment. Each treatment was replicated in 3 independent blocks, with 10 inflorescences per block.

[0033]

[0034] Fourteen days after the seedless treatment, the flower spikes were dipped in a 25 mg / L gibberellin aqueous solution for 5 seconds to induce fruit enlargement. Harvesting took place in August. After the fruits matured, five mature fruit spikes were randomly selected from each treatment group. Ten fruits were taken from the base, middle, and tip of each spike. The seedless rate was calculated (based on the absence of seeds within the berry, only normally mature fruits were counted, excluding seedless small fruits). Soluble solids (TSS) and total acid (TA) were measured using a handheld sugar-acid analyzer (PAL-BX / ACID F5), and the TSS / TA ratio was calculated. The L*, a, and b values ​​of the equatorial region of the fruit were measured using a spectrophotometer (Konica Minolta CM-2300d), and the color saturation (C*) was calculated. The results are shown in Table 4. A comparative image of the internal structure of fruits treated with only 150 μM melatonin for seedless treatment is shown below. Figure 1 As shown.

[0035]

[0036] Table 4 shows that melatonin (MT) treatment exhibits significant advantages in seedlessness rate and fruit quality, specifically as follows:

[0037] (1) Nucleus-free rate: Spraying 150μM MT alone (T2) can achieve 100% nucleation effect, which is significantly better than the control (CK, 0.88%) and GA3 alone (T1, 82%).

[0038] (2) Fruit quality: The TSS of the T2 treatment was the highest (19.26), which was significantly higher than that of the GA3 treatment group (T1, 18.18), indicating that the MT treatment can increase the sugar content of grapes; and the TSS / TA of the T2 treatment remained at a high level (33.22), which was better than the control (CK, 27.03), indicating that its fruit flavor was better; at the same time, the T2 treatment was better than the GA3 treatment (T1, L*=42.81, C*=19.12) in terms of brightness (L*=44.58) and color (C*=19.27), indicating that the fruit appearance quality was better.

[0039] In summary, treatment of grapes with 150 μM melatonin can achieve seedlessness effects close to or better than GA3, and can further improve fruit sugar content, acid-sugar ratio and appearance quality, demonstrating significant advantages as a novel seedlessness inducer.

[0040] Example 3

[0041] When melatonin and gibberellin are used as nucleation treatment agents, a cost comparison is performed, and the results are shown in Table 5:

[0042]

[0043] As shown in Table 5, the unit price of gibberellin is 8.92 times that of melatonin, while the required concentration of the working solution is more than 166.67 times that of melatonin. Because melatonin has a lower unit price and requires a much lower working concentration, the cost of preparing one liter of working solution is only one two-thousandth of that of gibberellin. Therefore, the cost-effectiveness of melatonin far exceeds that of gibberellin. For agricultural producers requiring large-scale treatment, this means a significant reduction in production material costs and substantial economic benefits.

[0044] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0045] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. Application of melatonin in the preparation of seedless grape formulations.

2. The application according to claim 1, characterized in that, The melatonin concentration is 100-200 μM.

3. The application according to claim 2, characterized in that, The melatonin concentration was 150 μM.

4. The application according to claim 1, characterized in that, The grapes in question are of the 'Sunshine Rose' variety.

5. A method for inducing seedlessness in grapes, characterized in that, During the peak flowering period of grapes, soak the inflorescences in a melatonin solution.

6. The method for inducing seedlessness in grapes according to claim 5, characterized in that, Soaking time is 4 to 6 seconds.

7. A preparation for inducing seedlessness in grapes, characterized in that, The active ingredient is melatonin.

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