Pollen suspension for improving fruit shape and quality of perfume pomelo as well as preparation method and application of pollen suspension

Abstract

The invention discloses a pollen suspension for improving the fruit shape and quality of a perfume pomelo as well as a preparation method and application of the pollen suspension. The pollen suspension is obtained by mixing a nutrient solution and Majia pomelo pollen; the nutrient solution is prepared from the following raw materials in parts by weight: 8 to 12 parts of xanthan gum, 5200 to 7800 parts of cane sugar, 36 to 54 parts of calcium gluconate, 4 to 6 parts of boric acid and 40000 to 60000 parts of water; the activity of the Majia pomelo pollen is not lower than 70%; the solid-to-liquid ratio of the Majia pomelo pollen to the nutrient solution is (0.2-0.6) g: 1L; the method can be used for improving the fruit shape and quality of the perfume pomelo, and compared with single-sexual fruiting in a natural state, the method can improve the fruit quality; the malformed fruit rate and the peel thickness of the perfume pomelo are reduced, the edible rate of fruits is improved, and the content of soluble solids in pulp is increased; compared with a traditional cross pollination mode, the method has the advantages that the seed characteristics can be optimized, the seed state of fruits can be obviously changed, and the industrial problem that quality improvement is accompanied by grain increase is solved; the pollination operation efficiency can be improved, and manual labor investment is saved.

Description

Technical Field

[0001] This invention relates to the field of plant cultivation technology, and in particular to a pollen suspension for improving the shape and quality of fragrant grapefruit, its preparation method, and its application. Background Technology

[0002] Fragrant Pomelo is a high-quality new pomelo variety from Linli County, Hunan Province, and is currently listed as a key characteristic industry supported by Linli County. This pomelo has sweet, crisp, and tender flesh with a lingering sweetness and is juicy and melts in the mouth. The fruit is also well-storable and has a promising market prospect. However, due to the self-incompatibility gene characteristic common in pomelos, under conventional monoculture planting methods, Fragrant Pomelo is mostly parthenocarpic, and the fruit is prone to quality defects such as irregular shape, thick peel (over 33mm), low edible rate (below 50%), and low soluble solids content (below 8.5%).

[0003] While cross-pollination can significantly improve fruit quality, existing technologies have obvious drawbacks: First, traditional cross-pollination relies on manual application of high-concentration pollen, which, while enhancing flavor, leads to a surge in the number of seeds and plumpness, thus reducing the edible rate and contradicting the market demand for "high-quality, low-seed" fruit. Second, manual application is extremely inefficient, requiring only about 0.5-1 acre per person per day, making it difficult to meet the demands of large-scale planting with a tight flowering period and abundant flowers in the peak blooming season of fragrant pomelos, and easily affecting yield due to untimely pollination.

[0004] Currently, while there are reports on pollination nutrient solutions for other fruit trees in existing technologies, most of them use single nutrient components or simple mixtures, and do not address the specific needs of pomelos, especially fragrant pomelos. Low-concentration spray pollination has been occasionally used in fruit trees such as apples and pears, but none of them have mentioned its regulatory effect on fruit and seed morphology, let alone revealed its special biological effects on fragrant pomelos.

[0005] In summary, the existing technology has the following problems: (1) Defects in parthenocarpy quality: Affected by the self-incompatible gene, under monoculture, the parthenocarpy deformity rate of Xiangshui pomelo is as high as 40%-50%, the peel thickness is more than 33mm, the edible rate is less than 50%, and the soluble solids are less than 8.5%, which is far from meeting the market demand for high-quality pomelo. Moreover, the existing technology cannot solve the problem of synergistic improvement of fruit shape, peel thickness, flavor and seed quantity at the same time.

[0006] (2) Disadvantages of traditional cross-pollination: Traditional cross-pollination does not select specific pollen for the self-incompatible genes of the fragrant pomelo, and uses high-concentration pollen for artificial pollination. Although it can improve the flavor, it will significantly increase the number of seeds per fruit, increase the plumpness of the seeds, and reduce the edible rate. At the same time, artificial pollination is inefficient and cannot meet the large-scale pollination needs during the peak flowering period of the fragrant pomelo, resulting in problems of tight time and heavy workload.

[0007] (3) Limitations of existing nutrient solutions and processes: Existing fruit tree pollination nutrient solutions are mostly single-component or simple mixtures, without considering the synergistic effects between components, and without formulating a solution specifically for the self-incompatibility characteristics of the fragrant pomelo. Low-concentration spraying in other fruit trees is only used to improve fruit set rate, and no regulatory effect on seed morphology has been found, which cannot meet the needs of simultaneous optimization of "quality-seed-efficiency" for the fragrant pomelo. Therefore, screening for specific male pollen that is compatible with self-incompatible genes, developing synergistic nutrient solutions, and establishing efficient low-concentration spray pollination processes have become key to solving the quality and production efficiency problems of fragrant pomelos. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention aims to solve three core technical problems: First, by screening specific paternal pollen that is compatible with self-incompatible genes, low-concentration pollen spraying can promote the formation of shriveled seeds in the fragrant pomelo, achieving a dual effect of "quality improvement and shriveled seed optimization," thus avoiding the problems of excessive seed quantity and plump seeds. Second, by developing a pollination nutrient solution with synergistic effects, clarifying the uniqueness of the distribution ratio of each component, providing precise nutritional support for pollen germination, successful pollination, and fruit development, ensuring quality and seed regulation effects. Third, by optimizing the pollination process, combining spraying timing, nozzle selection, and bee assistance, pollination efficiency can be significantly improved to meet the needs of large-scale planting, ultimately comprehensively improving the quality grade and market value of the fragrant pomelo fruit.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a pollen suspension for improving the shape and quality of fragrant pomelo, which is obtained by mixing nutrient solution and pollen from Majia pomelo. The nutrient solution is made from the following raw materials in parts by weight: Xanthan gum 8-12 parts, sucrose 5200-7800 parts, calcium gluconate 36-54 parts, boric acid 4-6 parts, water 40000-60000 parts; The vitality of the pollen from the Majia pomelo is no less than 70%; The solid-liquid ratio of the pomelo pollen to the nutrient solution is 0.2~0.6g:1L.

[0010] Furthermore, the nutrient solution is made from the following raw materials in parts by weight: 10 parts xanthan gum, 6500 parts sucrose, 45 parts calcium gluconate, 5 parts boric acid, and 50000 parts water.

[0011] Furthermore, when the activity of the pomelo pollen is 70%-95%, the solid-liquid ratio of the pomelo pollen to the nutrient solution is 0.6g:1L; When the vitality of the pomelo pollen is above 95%, the solid-liquid ratio of the pomelo pollen to the nutrient solution is 0.2-0.4g:1L.

[0012] In a second aspect, the present invention provides the application of any of the above-described pollen suspensions in spray pollination of grapefruit.

[0013] A third aspect of the present invention provides a method for preparing any of the above-described pollen suspensions, comprising the following steps: (1) Dissolving xanthan gum: Boil 2000-3000 parts by weight of water, add 8-12 parts by weight of xanthan gum to dissolve while stirring, filter through gauze and cool to room temperature; (2) Sucrose dissolution: Heat 8000-12000 parts by weight of water to 50-60℃ to dissolve 5200-7800 parts by weight of sucrose, stir and let it cool to room temperature; (3) Dissolution of other components: Dissolve 36-54 parts by weight of calcium gluconate and 4-6 parts by weight of boric acid in 400-600 parts by weight of water respectively, and stir until no crystal residue remains; (4) Mixing and adjusting the volume: Mix the solutions obtained in (1)-(3), add the remaining weight of water, stir evenly, and obtain the nutrient solution; (5) Mix the nutrient solution with pomelo pollen with a viability of not less than 70% and shake well to prepare a pollen suspension.

[0014] In a fourth aspect, the present invention provides a method for improving the shape and quality of fragrant grapefruit by spraying pollen suspensions of any of the above-described methods for fragrant grapefruit.

[0015] Furthermore, including: Two spray pollinations are carried out. The first spray is done at the beginning of the flowering period; the second spray is done two days later, when the number of flowers accounts for 50% of the total number of flowers. Use a single-hole fine mist nozzle, control the spray pressure at 0.2-0.3 MPa, and keep the nozzle 30-50 cm away from the tree trunk.

[0016] Furthermore, it also includes bee release assistance; after each spraying, 5,000-10,000 bees are released per acre for auxiliary pollination.

[0017] The beneficial effects of this invention include at least the following: (1) Significantly improved quality: Compared with parthenocarpy in the natural state, this technical solution can improve fruit quality: reduce the rate of deformed fruit and the thickness of peel of fragrant pomelo, increase the edible rate of fruit, and increase the content of soluble solids in the pulp. (2) Seed characteristics optimization: Based on the transfer of Majia pomelo pollen selected by self-incompatible gene screening + low concentration spraying process, compared with the traditional cross-pollination method, it can optimize seed characteristics, significantly change the state of fruit seeds, make the seeds mostly shriveled, and greatly reduce the total number of seeds, solve the industry problem of quality improvement accompanied by increased seed volume, meet consumers' demand for seedless or seedless seeds, and enhance market competitiveness. (3) Improve production efficiency: Improve the efficiency of pollination operations and save on manual labor input. The pollination efficiency of traditional manual pollination is about 0.5-1 mu per person per day, but the efficiency of diluted pollination is about 10 mu per person per day, which is 10-20 times that of manual pollination.

[0018] (4) The technology is highly universal: the equipment used in this technology is readily available, the nutrient solution components are low-cost, and the operation is simple and easy to master. It can be promoted and applied in large-scale planting bases of fragrant pomelo. Attached Figure Description

[0019] Figure 1 To dilute the pollinated fruit.

[0020] Figure 2 Fruits that have been artificially ordained. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0023] The core of this invention includes four key steps: "specific paternal pollen screening" based on the characteristics of self-incompatible genes, preparation of synergistic nutrient solution, preparation of low-concentration pollen suspension, and whole-tree spraying and assisted pollination, as detailed below: I. Selection of specific pollen: Based on the self-incompatible gene characteristics, phenological period (flowering concentrated in mid-to-late April), and quality defects of the Xiangshui pomelo, the initial screening of male parent varieties required meeting three core conditions: first, similar phenological periods to ensure synchronized pollination; second, carrying a genotype complementary to the self-incompatible gene of the Xiangshui pomelo to avoid pollination failure or abnormal seed development; and third, possessing the excellent traits of "large fruit, easy to peel, rich flavor, and thin peel." Through comparative testing, pollen from the Majia pomelo was selected as the optimal male parent.

[0024] II. Preparation of pollination nutrient solution (synergistic formulation of components) 1. Nutrient solution composition and unique ratio: The main components of the nutrient solution include water, xanthan gum (0.2g / L), sucrose (130g / L), calcium gluconate (0.9g / L), and boric acid (0.1g / L).

[0025] Xanthan gum: As a suspending agent, it can make pollen evenly dispersed in solution, reduce the sedimentation rate, and work synergistically with sucrose to form a stable "pollen-nutrient" microenvironment, preventing pollen aggregation; Sucrose: It not only provides energy for pollen germination, but also regulates the osmotic pressure of the solution and works synergistically with boric acid to promote pollen tube elongation.

[0026] Calcium gluconate: enhances pollen cell membrane stability and, together with boric acid, regulates signal transduction during pollen germination, thereby increasing pollination success rate.

[0027] Boric acid promotes the synthesis of pollen tube cell walls and works synergistically with other components to prevent pollen tube tip rupture.

[0028] 2. Preparation process: 1. Xanthan gum dissolution: Slowly add xanthan gum to boiling water (100℃) while stirring continuously for 15-20 minutes. Filter through 80-mesh gauze and cool to 25-30℃ (to avoid high temperature damaging subsequent components). Sucrose dissolution: Dissolve sucrose in 50-60℃ warm water, stir until completely dissolved, and then cool to room temperature (to prevent high temperature from affecting pollen viability). Mixing and adjusting to volume: Mix the cooled xanthan gum solution and sucrose solution with the dissolved calcium gluconate and boric acid solution, pour into a large-capacity container, stir well, and add water to adjust to the required volume.

[0029] III. Preparation of Low-Concentration Suspensions Take a clean container, add the above nutrient solution and pomelo pollen, and adjust the amount according to the pollen viability: (1) Pollen viability ≥95%: dosage 2-4g / mu, pollen concentration in suspension 0.2-0.4g / L; (2) Pollen viability 70%-95%: dosage 6g / mu, pollen concentration in suspension 0.6g / L; (3) Pollen viability <70%: Not recommended (experiments have shown that when viability is below 70%, the pollination success rate is low and the effect cannot be guaranteed).

[0030] When preparing the mixture, shake it thoroughly (shake manually for 3-5 minutes or stir magnetically for 10 minutes) to ensure that the pollen is evenly dispersed and there are no visible agglomerates.

[0031] IV. Whole-tree spraying and assisted pollination (optimizing efficiency and uniformity) 1. Spraying timing: Choose the transition period from the initial flowering stage to the full bloom stage, when the stigma secretion is at its highest and the pollen attachment and germination rate is the highest.

[0032] 2. Spraying equipment and parameters: Select a single-hole fine mist nozzle, control the spraying pressure at 0.2-0.3MPa, and keep the nozzle 30-50 cm away from the tree trunk.

[0033] 3. Bee release assistance: After each spraying, release 1-2 beehives per acre (about 5,000 bees per hive). The bees can carry pollen from the low-concentration suspension to supplement the flowers not covered by the spray (especially the hidden flowers inside the tree), so as to make the pollination even and avoid localized insufficient pollination caused by a single spray.

[0034] The following specific embodiments illustrate the solution proposed in this invention: Example 1 This technical experiment was conducted in Qinglong Village, Sheshiqiao Town, Linli County, Changde City, Hunan Province. Fragrant pomelo plants with uniform growth, normal flowers, and even flower quantity were selected as the experimental subjects. A total of more than 50 mu were pollinated, using 500L of suspension solution. A total of 6 workers completed the pollination within one day.

[0035] Step 1: Preparation of nutrient solution (taking 50L as an example) 1. Xanthan gum dissolution: Boil 2.5 kg of water, then slowly dissolve 10 g of xanthan gum while stirring. Filter through 80 mesh gauze and allow to cool to room temperature. 2. Dissolving sucrose: Dissolve 6500g of sucrose in 10kg of purified water by heating, stirring and cooling to room temperature; 3. Dissolving other components: Dissolve 45g of calcium gluconate and 5g of boric acid separately in 500ml of purified water, stirring until no crystals remain; 4. Mix and adjust to volume: Pour the above solution into a 100L large-capacity plastic container, add purified water to the 50L mark, and stir well for later use; Step 2: Low-concentration preparation: 1. Pollen viability determination: The TTC staining method was used to determine the pollen viability of the Majia pomelo used, which was 96.5%. 2. Preparation of low-concentration suspension: Add pollen to the corresponding proportion of nutrient solution (0.4g / L), stir evenly to ensure that the pollen is evenly distributed in the nutrient solution.

[0036] Step 3: Spraying and Assisted Pollination 1. Spraying timing: The first spraying pollination should be carried out on April 23, 2024, during the initial flowering stage; 2. Pour the prepared low-concentration suspension into a clean sprayer and shake gently. Select a single-hole fine mist nozzle for the sprayer. After preparation, begin pollination. Spray the open flowers with the nozzle, keeping a distance of 30-50 cm between the nozzle and the flower stigma. Spray evenly inside and outside the tree. Generally, a 16 L sprayer can pollinate 10-15 trees depending on the tree size. Pollen dosage: 4g / acre. 3. Bee release assistance: After the first spray, release one beehive per acre to supplement pollination of hidden flowers.

[0037] 4. Repeat pollination: On April 25, 2024 (two days later, when the number of flowers accounts for about 50% of the total number of flowers), a second pollination will be carried out, and the operation will be the same as the first time.

[0038] Experimental results: Table 1 shows the results of the number of deformed fruits in the experimental field using the five-point sampling method during the fruit ripening period (mid-November) for two consecutive years. Fruits with irregular characteristics, skin defects, multiple fruits connected together, and incomplete organ development were considered as deformed fruits. The statistical results show that compared with natural fruiting, the rate of deformed fruits of Xiangshui pomelo after dilution and pollination using the method of this embodiment was significantly reduced, and the fruit shape correction effect was significant.

[0039] Table 1. Effects of dilution pollination on deformed fruit of fragrant grapefruit

[0040] Table 2 shows the fruit quality of the fragrant pomelo after diluted pollination. As can be seen from Table 2, after diluted pollination, the peel thickness of the fruit decreased significantly, the edible rate increased significantly, and the soluble solids content increased significantly, indicating that diluted pollination of the fragrant pomelo using this technique can improve the fruit quality to a certain extent.

[0041] Table 2. Effects of dilution pollination on the fruit quality of fragrant pomelo.

[0042] Table 3 compares diluted pollination with artificial pollination. Diluted pollination significantly reduces the total number of seeds in the fruit, greatly improves pollination efficiency, solves the industry problem of increased seed quantity accompanying quality improvement, meets consumer demand for seedless or low-seed products, and enhances market competitiveness.

[0043] Table 3 Comparison of dilution pollination and manual pollination

[0044] Figure 1 To dilute the pollinated fruit, Figure 2 As can be seen from the longitudinal and transverse sections of the fruit in the figure, the seeds of the fruit obtained by diluting and pollinating with the present invention are mostly shriveled, while the seeds of the fruit obtained by traditional artificial pollination are plump and numerous.

[0045] Example 2 The comparison results using other parent genes in this embodiment are shown below: Table 4. Appearance quality of grapefruit pollinated with pollen from different paternal parents

[0046] Note: CK: Natural pollination of fragrant pomelo (control), ST: Fragrant pomelo × Shatin pomelo, HB: Fragrant pomelo × HB pomelo, MJ: Fragrant pomelo × Majia pomelo, GX: Fragrant pomelo × Guanxi honey pomelo, HR: Fragrant pomelo × red-fleshed honey pomelo; No identical lowercase letters in the same column indicate significant differences (p<0.05).

[0047] Table 5. Internal quality of grapefruit pollinated with pollen from different paternal parents

[0048] Note: CK: Natural pollination of fragrant pomelo (control), ST: Fragrant pomelo × Shatin pomelo, HB: Fragrant pomelo × HB pomelo, MJ: Fragrant pomelo × Majia pomelo, GX: Fragrant pomelo × Guanxi honey pomelo, HR: Fragrant pomelo × red-fleshed honey pomelo; No identical lowercase letters in the same column indicate significant differences (p<0.05).

[0049] The pollination combination of Xiangshui pomelo and Majia pomelo can achieve the dual effect of "quality improvement and shriveled seed optimization" to a certain extent. Among the above-mentioned parent plants, Majia pomelo has a phenological period that is highly synchronized with Xiangshui pomelo, carries a genotype that is complementary to the self-incompatible genes of Xiangshui pomelo, and has the excellent traits of "large fruit that is easy to peel, strong flavor, and thin peel".

[0050] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0051] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A pollen suspension for improving the shape and quality of fragrant grapefruit, characterized in that, It is obtained by mixing nutrient solution and pomelo pollen; The nutrient solution is made from the following raw materials in parts by weight: Xanthan gum 8-12 parts, sucrose 5200-7800 parts, calcium gluconate 36-54 parts, boric acid 4-6 parts, water 40000-60000 parts; The vitality of the pollen from the Majia pomelo is no less than 70%; The solid-liquid ratio of the pomelo pollen to the nutrient solution is 0.2~0.6g:1L.

2. The pollen suspension according to claim 1, characterized in that, The nutrient solution is made from the following raw materials in parts by weight: Xanthan gum 10 parts, sucrose 6500 parts, calcium gluconate 45 parts, boric acid 5 parts, water 50000 parts.

3. The pollen suspension according to claim 1, characterized in that, When the activity of the pomelo pollen is 70%-95%, the solid-liquid ratio of the pomelo pollen to the nutrient solution is 0.6g:1L. When the vitality of the pomelo pollen is above 95%, the solid-liquid ratio of the pomelo pollen to the nutrient solution is 0.2-0.4g:1L.

4. The use of the pollen suspension according to any one of claims 1-3 in spray pollination of grapefruit.

5. The method for preparing the pollen suspension according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Dissolving xanthan gum: Boil 2000-3000 parts by weight of water, add 8-12 parts by weight of xanthan gum to dissolve while stirring, filter through gauze and cool to room temperature; (2) Sucrose dissolution: Heat 8000-12000 parts by weight of water to 50-60℃ to dissolve 5200-7800 parts by weight of sucrose, stir and let it cool to room temperature; (3) Dissolution of other components: Dissolve 36-54 parts by weight of calcium gluconate and 4-6 parts by weight of boric acid in 400-600 parts by weight of water respectively, and stir until no crystal residue remains; (4) Mixing and adjusting the volume: Mix the solutions obtained in (1)-(3), add the remaining weight of water, stir evenly, and obtain the nutrient solution; (5) Mix the nutrient solution with pomelo pollen with a viability of not less than 70% and shake well to prepare a pollen suspension.

6. A method for improving the shape and quality of grapefruit, characterized in that, Perfume grapefruit spray pollination was performed using the pollen suspension described in any one of claims 1-3.

7. The method according to claim 6, characterized in that, include: Two spray pollinations are carried out. The first spray is done at the beginning of the flowering period; the second spray is done two days later, when the number of flowers accounts for 50% of the total number of flowers. Use a single-hole fine mist nozzle, control the spray pressure at 0.2-0.3 MPa, and keep the nozzle 30-50 cm away from the tree trunk.

8. The method according to claim 7, characterized in that, It also includes bee release assistance; after each spraying, 5,000-10,000 bees are released per acre for auxiliary pollination.

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