A double batch harvesting cultivation method for promoting winter fruit of cherimoya by avoiding summer fruit

Abstract

The application discloses a double-batch harvesting cultivation method for summer-fruit-avoiding and winter-fruit-promoting of cherimoya, and belongs to the technical field of fruit planting and cultivation. The double-batch harvesting cultivation method is specifically as follows: natural fruit setting is thinned in March to April; the upper part of the crown is pruned in the last ten days of June to the first ten days of July, and the first pollination is carried out in July, so that early winter fruits mature in November are cultivated; the lower part of the crown is pruned in the last ten days of August to the middle ten days of September, and the second pollination is carried out in the middle ten days of October, so that late winter fruits mature in the next March to April are cultivated. Through the time and area pruning of single plants and the synergistic regulation of fertilization and water, the double-batch high-quality winter fruit production is realized, the summer fruit cracking problem is effectively avoided, and the fruit quality and economic benefits are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of fruit planting and cultivation technology, and relates to a method for cultivating custard apples in hot and dry valley climate zones, specifically a double-harvest cultivation method for custard apples that promotes winter fruit production without summer fruit production. Background Technology

[0002] Custard apple (also known as sugar apple) is a tropical fruit whose growth is extremely sensitive to accumulated temperature and low winter temperatures. It is best suited for cultivation in areas with an average annual temperature above 20℃ and no frost in winter. Currently, major custard apple producing areas in my country, such as Hainan, Guangdong, Guangxi, and Fujian, generally adopt the cultivation method of "seasonal cultivation, summer and autumn harvest," with the fruit harvest period highly concentrated from June to November each year. In the hot and dry river valley climate zone of northern tropical my country (such as the Jinsha River, Yuan River, and Nu River basins), the unique geographical conditions have created a climate characterized by abundant heat, ample sunshine, drought, and large diurnal temperature differences, earning it the reputation of a "natural greenhouse." The higher average annual temperature, richer heat resources, and more significant diurnal temperature differences in the hot and dry river valley regions are extremely conducive to the accumulation of sugar and the formation of flavor substances in custard apples, possessing the potential to produce high-quality fruit. However, when the mainstream "off-season cultivation" method is directly applied to this region, the fruit development period overlaps significantly with the summer high temperatures, strong sunlight, and rainy season, resulting in widespread problems such as sunburn, fruit cracking, and severe pre-harvest fruit drop. This leads to a low rate of marketable fruit and unstable quality, making it difficult to transform the region's unique climatic advantages into industrial benefits.

[0003] To overcome the quality defects of summer fruits, existing technologies have employed agronomical measures such as pruning to postpone the ripening period to winter. CN118402425B discloses a method for sparse planting of pineapple custard apples in hot and dry valleys. This method divides the fruit trees into different batches within the orchard, and then, from late April to late July, heavily prunes the fruit trees in different batches at different times in five separate periods. This allows for staggered harvesting throughout the orchard from November to March of the following year, yielding winter fruit. Essentially, this method extends the overall supply period of the orchard by allowing fruit to ripen in batches on different trees, but it does not fundamentally change the limited yield per tree and the single harvest period. Therefore, its effect on increasing the yield per tree and further staggering market entry is limited. Furthermore, this technology relies on high-input measures such as sparse planting, complex soil improvement, and high-standard precision irrigation, resulting in complex management and stringent production conditions. This limits its universality and potential for widespread application under conventional management conditions. Furthermore, although such production period adjustment techniques have successfully cultivated winter fruit, there is still a significant overlap in the market launch periods of different production areas, creating new concentrated market launch windows. The problem of homogeneous competition between production areas has not been fundamentally solved, and the room for price increases remains limited.

[0004] Therefore, the existing methods for regulating the production period of custard apples still have significant shortcomings in further optimizing the supply pattern, achieving more thorough staggered market entry, and increasing the yield per tree. A more efficient and practical new technology solution is urgently needed. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the existing seasonal cultivation method for custard apples, when applied to the dry and hot valley area of ​​Yuanjiang, has the problem that the critical development period of the fruit overlaps with the high temperature, strong light and rainy season in summer, resulting in prominent problems of sunburn, fruit cracking and pre-harvest fruit drop, and making it difficult to continuously guarantee the commercial fruit rate and the stability of fruit quality.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows.

[0007] This invention provides a double-harvest cultivation method for custard apples that promotes winter fruit production and avoids summer fruit production. The double-harvest cultivation method is applied to a single custard apple tree and specifically includes the following steps:

[0008] S1. Abandon summer fruit: In March and April each year, remove or suppress all natural fruit set on the custard apple tree;

[0009] S2. First batch of flowering and fruit setting: From late June to early July each year, the upper half of the tree is pruned to promote flowering, accounting for 55-65% of the total tree size; after the first batch of flowers sprout, the first artificial pollination is carried out during the peak flowering period.

[0010] S3. Second round of flowering and fruit setting: From late August to mid-September each year, the lower half of the tree is pruned to promote flowering, accounting for 35-45% of the total tree area; after the second batch of flowers emerges, a second artificial pollination is carried out during the peak flowering period;

[0011] S4. Harvesting in batches: Fruits pollinated in step S2 are considered early winter fruits and are harvested from November to December of the same year; fruits pollinated in step S3 are considered late winter fruits and are harvested from March to April of the following year.

[0012] Furthermore, in step S2 above, the amount of pruning for promoting flowering accounts for 60% of the total amount of pruning on the tree.

[0013] Furthermore, in step S3 above, the amount of pruning for promoting flowering accounts for 40% of the total amount of pruning on the tree.

[0014] Furthermore, the time interval between the first and second rounds of flower-inducing pruning was 65-75 days.

[0015] In step S2 or S3 above, the flower-promoting pruning includes: selecting a current-year, moderately grown branch with a diameter of 0.8-1cm and a color transitioning from blue to brown; cutting the branch 13-17cm from the base, retaining a stub with 2-3 dormant buds at the top; immediately after pruning, thoroughly removing the petioles and stipules from the stub and cleaning up any overgrown branches.

[0016] Furthermore, during the above pruning, the cut plane should form an angle of 43 to 47 degrees with the branch axis, and the slanted cut should face outwards from the tree crown.

[0017] In step S2 or S3 above, if the highest temperature on a certain day is ≥38℃ and the relative humidity is below 30% within 10 days after the flowering-promoting pruning, then it is necessary to spray the outer side of the tree canopy and the branch stump area with a fine mist nozzle in the morning and evening of that day.

[0018] In step S3 above, within 24 hours after the flower-promoting pruning, a low-nitrogen, high-potassium water-soluble fertilizer is applied for root irrigation, and seaweed foliar fertilizer is sprayed.

[0019] Furthermore, 7-10 days after the above-mentioned pruning to promote flowering, spray seaweed foliar fertilizer again.

[0020] In step S3 above, the second artificial pollination includes: collecting male flowers at 15:00-16:00 the day before pollination and placing them in a 25℃ environment for 10-14 hours to promote anther dehiscence; and using freshly released pollen to pollinate the semi-open female flowers before 8:00 on the day of pollination.

[0021] In the above-mentioned double-harvest cultivation method, during the young fruit stage of both batches of flowers, deformed fruits, diseased and pest-infested fruits, and overly dense fruits should be removed in a timely manner to ensure that the fruits are evenly distributed.

[0022] In the above-mentioned double-harvest cultivation method, before the two flowering prunings or during the fruit enlargement period, a complete nutrient fertilizer mainly composed of phosphorus and potassium fertilizer is applied.

[0023] The beneficial effects of this invention are as follows: By actively abandoning summer fruit and adjusting the fruit development period to the more suitable winter and spring seasons, the double-harvest cultivation method of this invention effectively avoids the adverse effects of high temperatures, strong sunlight, and rainy seasons in the dry-hot valleys on fruit development. This significantly reduces the incidence of sunburn, fruit cracking, and pre-harvest fruit drop, resulting in a stable improvement in the marketable fruit rate and fruit quality. Simultaneously, the large diurnal temperature range in the dry-hot valleys during winter and spring is conducive to the accumulation of sugar and dry matter, producing winter fruits with a regular shape, smooth surface, high sweetness, rich flavor, and stronger storage and transportation resistance.

[0024] This invention achieves a double-harvest method by precisely pruning individual custard apple trees in June and September, respectively, according to different regions and proportions, combined with appropriate artificial pollination. This allows for the harvesting of early winter fruit in November and late winter fruit in March and April of the following year. This method not only staggers the harvest season from traditional production areas, improving economic benefits, but also ensures efficient allocation and concentrated utilization of tree nutrients through staggered harvesting, avoiding excessive nutrient consumption and promoting robust tree growth and sustainable orchard production. This invention can transform the climatic potential of hot and dry valleys into industrial benefits, which is of great significance for promoting the upgrading and sustainable development of my country's custard apple industry. Attached Figure Description

[0025] Figure 1 A schematic diagram of the first-stage flowering pruning in a double-harvest cultivation method for custard apples that promotes winter fruit production and avoids summer fruit production.

[0026] Figure 2 A schematic diagram of the first-stage flowering pruning in a double-harvest cultivation method for custard apples that promotes winter fruit production and avoids summer fruit production.

[0027] Figure 3 Figure showing the early winter fruit cultivation process of the double-batch harvesting cultivation method for custard apples, which aims to prevent summer fruit production and promote winter fruit production.

[0028] Figure 4 A diagram illustrating the cultivation of late-winter fruit using a double-harvest cultivation method for custard apples that promotes winter fruit production without summer fruit production.

[0029] Figure 5 This describes the cultivation process and status of custard apple trees using a winter-harvesting cultivation method under production period regulation technology. Detailed Implementation

[0030] To make the technical problems, solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with the embodiments. Unless otherwise defined, all technical terms used herein have the same meaning as understood by one of ordinary skill in the art.

[0031] A dual-harvest cultivation method for custard apples suitable for hot and dry valleys, which promotes winter fruit production and eliminates summer fruit production, is proposed. This method integrates flower-inducing pruning and two artificial pollination processes on the same custard apple tree in stages, regions, and proportions. By precisely controlling the pruning time, location, stub length, petiole treatment, and microenvironment adjustment, two batches of flower bud differentiation are induced, forming a dual-peak harvest method of "early winter fruit + late winter fruit". Ultimately, this method eliminates low-value summer fruit and achieves high-quality, efficient, and staggered supply. The specific steps include the following.

[0032] Step 1, abandon summer fruit: In March and April each year, completely remove or lightly prune all natural fruit set, so that the tree's nutrients can be concentrated on the subsequent differentiation of winter fruit.

[0033] Step Two, Double-Batch Pruning to Promote Flowering and Fruit Set: From late June to early July each year, the upper half of the tree is pruned to promote flowering, accounting for 55% to 65% of the total tree area. At this time, the lower part of the tree remains in a complete vegetative growth state. After pruning, the tree's condition is as follows: Figure 1 As shown; after the first batch of flowers sprouts, the first artificial pollination is carried out during the peak flowering period. From late August to mid-September each year, when the early winter fruits on the upper part of the tree have set fruit stably, the lower half of the tree is pruned a second time to promote flowering, with the pruning amount accounting for 35% to 45% of the entire tree. At this time, the tree presents a form where the upper part is fruit-bearing and the lower part is pruned, as shown in the figure. Figure 2 As shown; after the second batch of flowers sprouts, a second artificial pollination will be carried out during the peak flowering period.

[0034] In one embodiment of the present invention, the pruning to promote flowering needs to be carried out on the same plant at two key periods, specifically including the following steps;

[0035] (1) Branch selection: Select target pruning branches. Select current-year moderate branches with a diameter between 0.8 and 1 cm and a color transitioning from green to brown. Branches that are infected with pests and diseases, branches that are thin and malnourished, and branches that are weak due to long-term shade inside the canopy should be skipped and not selected or pruned;

[0036] (2) Pruning: Prune the target branch selected in step (1). Cut about 15 cm from the base of the branch; the part retained in this section is called the "stump". When pruning, it is necessary to ensure that the top part of the stump retains 2 to 3 healthy, plump dormant buds. The cut plane should be at an angle of about 45 degrees to the branch axis, and the cut slope should face away from the center of the crown, i.e., outward, so that rainwater can slide off and minimize water accumulation at the cut, reducing the risk of rot.

[0037] (3) Remove petioles: After completing the pruning operation (within 30 minutes), immediately clean up any leaves that may be on the branch stump. Pinch the base of the petiole with your thumb and forefinger and wipe it off from the tip in one go. This process is called "removing petioles". If petioles remain, they will release ethylene and phenolic substances that inhibit growth during the degradation process, which may delay the germination time of adjacent dormant buds by 5 to 7 days. Therefore, it is required to completely remove the petioles and the stipules attached to them.

[0038] (4) Remove vigorous shoots: Inspect the entire tree to identify and treat vigorous shoots, especially those that grow rapidly, stand upright, and resemble "rockets." These shoots should not be pruned, but should be thoroughly removed from the base where they connect with the trunk or main branch using tools such as a handsaw, i.e., "one-cut removal." This operation can effectively avoid the "water-pumping effect" caused by the excessive "apical dominance" of vigorous shoots, which will deplete the tree's nutrients and cause the fruiting branches in the middle and lower parts of the tree to weaken or even die due to nutrient deficiency.

[0039] (5) Post-pruning protection: Within 10 days after completing all the above pruning steps, it is necessary to closely monitor the weather forecast. If the forecast indicates that the daily maximum temperature will reach or exceed 38℃ and the relative humidity is below 30%, protective measures should be initiated. Specifically, spray the outer side of the tree canopy, especially the branch stump area, with a fine mist sprayer every morning and evening. Spray twice a day to locally increase humidity and lower temperature, preventing the delicate new buds from drying out due to extreme hot and dry weather.

[0040] In one embodiment of the present invention, the first round of flowering-inducing pruning is carried out from around June 20 to July 1 each year, focusing on pruning the upper half of the tree, with the pruning amount accounting for 60% of the entire tree. The first batch of flowers will sprout 7 to 14 days after the first round of flowering-inducing pruning (around July), and the first artificial pollination will be carried out during the peak flowering period.

[0041] In one embodiment of the invention, the second batch of flower-inducing pruning is carried out from around August 25 to September 15 each year, focusing on pruning the lower half of the tree, with the pruning amount accounting for 40% of the entire tree. The second batch of flowers will sprout 7 to 14 days after the second batch of flower-inducing pruning (around October), and a second artificial pollination will be carried out during the peak flowering period.

[0042] The second round of pruning is the core step in inducing flowering. During this period, the average nighttime temperature drops below 20℃ and the sunshine duration is less than 11.5 hours, causing the lateral buds of the tree to easily enter a "semi-dormant" state. Conventional leaf removal is unlikely to effectively promote flower bud differentiation. Therefore, within 24 hours after the completion of the second round of pruning, a low-nitrogen, high-potassium water-soluble fertilizer is first applied through root irrigation, followed by a foliar spray of seaweed extract fertilizer, and then sprayed again after an interval of 7-10 days. Through the synergistic regulation of "pruning-root zone promotion and control-foliar nutrition," the proportion of excessive shoots can be controlled below 8% within two weeks, and phenotypic changes such as thicker leaves and a darker green leaf color can be observed, thereby significantly improving the flower bud differentiation rate.

[0043] Furthermore, during the second artificial pollination, the lower ambient temperature during this stage can delay flower opening and result in less mature male flowers. Therefore, it is advisable to gently collect whole male flowers around 4 PM (4:00 PM), place them on clean cardboard, and leave them in a 25°C air-conditioned environment for approximately 12 hours. By around 6 AM the following morning, the anthers will naturally dehisce, revealing a distinctly yellow pollen. Before 8 AM (8:00 AM), use a brush to collect the freshly released pollen and promptly apply it to the stigma of the female flower to complete the pollination.

[0044] In one embodiment of the present invention, the first and second batches of flower-inducing pruning need to be spaced 65 to 75 days apart to ensure carbohydrate reflux and compensatory root growth.

[0045] In one embodiment of the present invention, during the young fruit stage of two batches of flowers, deformed fruits, diseased and pest-infested fruits, and overly dense fruits are removed in a timely manner to ensure that the fruits are evenly distributed.

[0046] In one embodiment of the invention, before two flowering-promoting prunings and during key phenological periods such as the fruit enlargement period, a complete nutrient fertilizer mainly composed of phosphorus and potassium fertilizers, supplemented with appropriate amounts of nitrogen fertilizer and trace elements, is applied in a timely manner. Combined with irrigation, soil conditioners such as photosynthetic bacteria inoculants can be applied to optimize the rhizosphere microenvironment, enhance tree vigor, and improve fruit quality.

[0047] In one embodiment of the present invention, the occurrence of pests and diseases is relatively mild in winter and spring, and prevention is the main focus. Agricultural and physical control methods are adopted, and highly effective and low-toxicity biological pesticides are used for targeted control when necessary.

[0048] Step 3, harvesting in batches: Fruits formed by the first artificial pollination are considered early winter fruits and are harvested from November to December of the same year; fruits formed by the second artificial pollination are considered late winter fruits and are harvested from March to April of the following year.

[0049] In one embodiment of the present invention, the fruit formed after the first pruning and artificial pollination has a growth period of about 120 days and matures around November. It can be harvested when the peel turns from green to light yellow-green, the scales on the surface become smooth and the grooves between the scales turn light yellow. This is an early winter fruit, and the number of fruits per plant is about 40 to 50.

[0050] In one embodiment of the present invention, the fruit formed by the second pruning and artificial pollination has a growing period of about 150 days due to the decrease in ambient temperature in the later stage of growth. It matures in March or April of the following year. When the peel turns from green to light yellow-green, the scales on the surface become smooth and the grooves between the scales turn light yellow, it can be harvested. This is a late winter fruit, and the number of fruits per plant is about 30 to 40.

[0051] In one embodiment of the present invention, the harvesting should be carried out on a sunny day before 10:00 am or after 4:00 pm. Use fruit shears to cut the fruit from the stem while keeping the fruit bag, and gently place it in a fruit basket. After transporting it back, remove the fruit bag and sort it in a cool place. The entire process should be handled gently to avoid scratching or squeezing the fruit skin.

[0052] This invention employs a strategy of pruning 60% of fruit branches in late June and 40% in late August to lower the base yield of the second batch of fruit. This effectively mitigates and reduces the risk of yield loss caused by climate fluctuations such as chilling injury in January (which can easily lead to "frosting" of the fruit flesh) and a sharp rise in temperature in March (which can easily trigger fruit bud break and exacerbate physiological fruit drop). By systematically implementing the above methods, the germination rate and uniformity of dormant buds can be significantly improved, excellent fruiting branch groups can be quickly formed, and the nutritional balance of the tree can be maintained, laying the foundation for high, stable, and high-quality fruit production.

[0053] The following specific embodiments will be provided to explain the solution of the present invention. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially. Example

[0054] This invention selected sites in the Yuanjiang dry-hot valley region at an altitude of 400-1200m and implemented two custard apple cultivation methods: "winter harvesting under production period regulation technology" and "double-batch harvesting to promote winter fruit without summer fruit". The important phenological periods, cost input and output benefits of the two cultivation methods were compared. The specific experimental process is as follows.

[0055] 1. Test location and time

[0056] A certain custard apple orchard base in Yuanjiang County, Yuxi City, Yunnan Province (longitude 102°85´, latitude 23°52´); terrain: sloping, altitude 553.3m; soil type: sandy loam; cultivation methods are "winter harvesting under production period regulation technology" and "double-batch harvesting to promote winter fruit without summer fruit"; among them, the "double-batch harvesting cultivation method to promote winter fruit without summer fruit" is counted as an example, and the "winter harvesting cultivation method under production period regulation technology" is counted as a comparative example.

[0057] Experimental period: 2021-2024. In 2019, two-year-old rootstock varieties of common custard apple were planted with a spacing of 3m×4m and 55 trees per mu. Grafting was carried out in 2018 with pineapple custard apple and AP custard apple varieties. High and stable yields began in 2021.

[0058] 2. Comparative analysis of the two cultivation methods

[0059] (1) Comparison of important phenological periods of the two cultivation methods. The important phenological periods of the example are shown in Table 1, and the important phenological periods of the comparative example are shown in Table 2.

[0060] Table 1 Important phenological periods of the examples

[0061]

[0062] Table 2 Important phenological periods for comparative examples

[0063]

[0064] Comparative analysis shows that the embodiments of the present invention achieve effective regulation of phenological periods through two-stage pruning. In addition, the second batch of fruits has a longer growth period due to the lower temperature in the later stage of growth, forming a high-value market window from March to April. This constitutes an important basis for the high economic benefits of the method.

[0065] The cultivation of the first batch of fruit (early winter fruit) in the example is as follows: Figure 3 As shown in the figure, the upper branches of the tree are bearing fruit well, with young fruits evenly distributed, while the lower branches have been pruned. The cultivation process of the second batch of fruit (late winter fruit) is as follows. Figure 4 As shown in the figure, the first batch of fruits on the upper part of the tree has entered the bagging management stage, while the lower branches are gradually setting fruit, exhibiting the characteristic of two batches of fruits developing together. The cultivation process is illustrated in the comparative figure. Figure 5 As shown in the figure, the tree has not undergone zonal pruning, all fruits have matured in a concentrated manner, and the fruits are evenly distributed in all parts of the canopy and are all under bagging management.

[0066] (2) Analysis of input costs, output, net income and economic value of the two cultivation methods in 2023 and 2024. The results are shown in Tables 3 to 6.

[0067] Table 3 Input Costs

[0068]

[0069] Note: Cost is calculated per acre, with 55 trees / acre and a fixed value of 3m×4m. In the example, the input costs of field management from the second batch of fruit harvest to the first batch of fruit harvest are all included in the input costs of the first batch of fruit. The input costs of the second batch of fruit only involve the costs of pollination, bagging, covering, spraying, and harvesting.

[0070] Table 4 Output

[0071]

[0072] Table 5 Net Income

[0073]

[0074] Table 6 Economic Value

[0075]

[0076] Based on the data in Tables 3-6, a comparative analysis of the economic benefits of the two cultivation methods was conducted. Experimental data shows that the embodiments of this invention exhibited significant economic advantages during the trial period of 2023-2024. Compared with the comparative method, the cultivation method of this invention achieved a yield increase of 25.00-30.60% while increasing the average unit price by 4.80-5.30%, ultimately leading to a 33.36-39.47% increase in output value. Although the total input increased by 19.03-24.34%, the net profit increased by 37.95-52.07%, with a cost-return ratio far exceeding that of the traditional method, demonstrating excellent input-output efficiency and a higher cost-return ratio.

[0077] In summary, the double-harvest cultivation method for custard apples, which promotes winter fruit production without summer fruiting, provided by this invention, successfully achieves the separate production of early winter fruit (maturing in November) and late winter fruit (maturing in March-April of the following year) on the same plant through a timed and zoned pruning strategy on the same plant, combined with appropriate fertilizer and water management and artificial pollination techniques. This method effectively avoids the adverse effects of high temperature and humidity in the dry-hot valley region during summer, and significantly improves fruit sugar accumulation and flavor quality by adjusting the main fruit development period to winter. Two years of field trials show that, with a moderate increase in management input, this method can achieve a 33.36-39.47% increase in output value and a 37.95-52.07% increase in net profit, demonstrating good promotional value and application prospects.

Claims

1. A double-harvest cultivation method for custard apples that promotes winter fruit production and avoids summer fruiting, characterized in that: The double-harvest cultivation method is applied to individual custard apple trees and includes the following steps: S1. Abandon summer fruit: In March and April each year, remove or suppress all natural fruit set on the custard apple tree; S2. First batch of flowering and fruit setting: From late June to early July each year, the upper half of the tree is pruned to promote flowering, accounting for 55-65% of the total tree size; after the first batch of flowers sprout, the first artificial pollination is carried out during the peak flowering period. S3. Second round of flowering and fruit setting: From late August to mid-September each year, prune the lower half of the tree to promote flowering. Within 24 hours after the pruning, apply a low-nitrogen, high-potassium water-soluble fertilizer for root irrigation and spray with seaweed foliar fertilizer. 7-10 days after the pruning, spray with seaweed foliar fertilizer again. The pruning amount accounts for 35-45% of the entire tree. After the second batch of flowers emerges, carry out a second artificial pollination during the peak flowering period. S4. Harvesting in batches: Fruits pollinated in step S2 are harvested as early winter fruits from November to December of the same year. The fruits formed by pollination in step S3 are considered late-winter fruits and are harvested from March to April of the following year. In step S2 or S3, the flower-promoting pruning includes: selecting current-year moderate branches with a diameter of 0.8~1cm and a color transitioning from blue to brown; Cut the branch 13-17cm from the base, leaving a stub with 2-3 dormant buds at the top; immediately after pruning, completely remove the petioles and stipules from the stub and remove any overgrown branches.

2. The double-harvest cultivation method for custard apples that promotes winter fruit production without summer fruiting, as described in claim 1, is characterized in that: In step S2, the amount of pruning for promoting flowering accounts for 60% of the total pruning amount of the tree; In step S3, the amount of pruning for promoting flowering accounts for 40% of the total amount of pruning on the tree.

3. The double-harvest cultivation method for custard apples that promotes winter fruit production without summer fruit, as described in claim 2, is characterized in that: When pruning, the cut surface should form an angle of 43 to 47 degrees with the branch axis, and the slanted cut surface should face outwards from the tree crown.

4. The double-harvest cultivation method for custard apples that promotes winter fruit production without summer fruit, as described in claim 1, is characterized in that: In step S2 or S3, if the highest temperature on a certain day is ≥38℃ and the relative humidity is below 30% within 10 days after the flowering-promoting pruning, then a fine mist sprayer should be used to spray the outer side of the tree canopy and the branch stump area in the morning and evening of that day.

5. The double-harvest cultivation method for custard apples that promotes winter fruit production without summer fruit, as described in claim 1, is characterized in that: In step S3, the second artificial pollination includes: collecting male flowers at 15:00-16:00 the day before pollination and placing them in a 25℃ environment for 10-14 hours to promote anther dehiscence; and using freshly released pollen to pollinate the semi-open female flowers before 8:00 on the day of pollination.

6. The double-harvest cultivation method for custard apples that promotes winter fruit production without summer fruit, as described in claim 1, is characterized in that: During the young fruit stage of both batches of flowers, timely thinning of deformed, diseased, and overly dense fruits is necessary to ensure even fruit distribution.

7. The double-harvest cultivation method for custard apples that promotes winter fruit production without summer fruit, as described in claim 1, is characterized in that: Before two flowering-promoting prunings or during the fruit enlargement period, apply a complete nutrient fertilizer mainly composed of phosphorus and potassium.

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