Lotus root seedling breeding method based on leaf cutting technology

Abstract

The invention provides a lotus root seedling breeding method based on a leaf cutting technology, which comprises the following steps: screening 'DongRiver early lotus root', 'May early' or 'Eulian 10' varieties, performing whole field leaf cutting at a position 30cm above the water surface at the initial stage of closing rows, and spraying 0.5% monopotassium phosphate solution twice when closing the rows again. According to the method, vegetative growth of a specific variety of lotus roots is efficiently turned into reproduction growth through row closing, leaf cutting and monopotassium phosphate spraying. By means of the method, the number of lotus roots planted per mu can be remarkably increased to 2735 from conventional 934, the increasing rate reaches 193%, meanwhile, terminal buds of the produced lotus roots are plump, internodes are short and thick, the quality is remarkably improved, blooming is restrained, biological mixing is eradicated, the purity of the lotus roots is guaranteed, the production number, quality and purity of the lotus roots are improved, the cost of the lotus roots is saved by more than 1600 yuan per mu, and economic benefits are remarkable.

Description

Technical Field

[0001] This invention belongs to the field of lotus root cultivation technology, specifically relating to a method for propagating lotus root seedlings based on leaf cutting technology. Background Technology

[0002] Lotus root production typically relies on underground rhizomes, or seed rhizomes, for asexual reproduction. However, traditional seed rhizome propagation methods have long suffered from a bottleneck problem that has remained unresolved: a low propagation coefficient, resulting in a severe shortage of qualified seed rhizomes per unit area.

[0003] Currently, the amount of seed lotus used per mu (approximately 0.16 acres) is as high as 600 to 800 kilograms, but only about 900 to 1,000 seed lotus roots can be harvested per mu the following year, resulting in an extremely low propagation coefficient (the ratio of the amount of seed lotus roots produced to the amount of seed lotus roots input). This "high input, low output" model directly leads to high seed costs in lotus root production, greatly compressing planting efficiency and restricting the large-scale development of the lotus root industry.

[0004] The root cause of this problem lies in the fact that, under conventional cultivation management, the photosynthetic products of lotus plants are preferentially supplied to the vigorous growth of the above-ground lotus leaves and later flowering and fruiting, resulting in insufficient nutrient allocation to the underground rhizomes and difficulty in effectively stimulating branching. Therefore, the number of daughter rhizomes that each seed rhizome can form is limited, ultimately resulting in a low number of seed rhizomes per acre and a low total yield. Summary of the Invention

[0005] This invention provides a method for propagating lotus seedlings based on leaf cutting technology, aiming to solve the technical problem of low seed quantity in the existing lotus propagation technology.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for propagating lotus seedlings based on leaf-cutting technology, comprising the following steps:

[0008] S1. In the early stage of the first closure of the lotus rows, the leaves of the whole field should be cut at a depth of 30cm above the water surface;

[0009] S2. After cutting the leaves, when the lotus roots close up again, spray the leaves with a 0.5% potassium dihydrogen phosphate solution before 9 am or after 4 pm on a sunny day.

[0010] S3. Repeat the spraying with a 0.5% potassium dihydrogen phosphate solution after a 10-day interval;

[0011] The lotus root varieties mentioned are "Donghe Early Lotus Root", "May Early Lotus Root" or "Elian No. 10".

[0012] In a preferred embodiment, the lotus root leaves are harvested in late May during step S1.

[0013] Based on the above plan, late May is usually the early stage of the transition of lotus plants from vigorous vegetative growth to tuber formation and branching. At this time, the lotus leaves have basically "closed off the canopy". Cutting the leaves at this time is equivalent to stopping photosynthesis. In order to prolong life, the plant will be forced to shift the priority of supplying stored and remaining nutrients from the above-ground parts to the underground parts, so as to accelerate the development and branching of underground rhizomes, thereby promoting the formation of propagules.

[0014] In the preferred embodiment, the planting density of lotus root is 1.5-2m row spacing and 1-1.5m plant spacing, with a seed quantity of 600-800 kg per mu and 1-2 seed lotus roots per hole.

[0015] Based on the above plan, planting density directly determines the timing of lotus leaf canopy closure. This density range ensures that the lotus plants reach the ideal state of "canopy closure without excessive shading" around late May. If the planting is too dense, canopy closure will occur too early, resulting in weak plants with insufficient nutrient accumulation, making leaf cutting at this time devastating. If the planting is too sparse, canopy closure will be delayed, missing the optimal physiological window for leaf cutting. A row spacing of 1.5-2m provides the necessary operational space for manual or mechanical field leaf cutting, ensuring that each plant is treated evenly.

[0016] In the preferred embodiment, the lotus root is harvested in mid-March of the following year, and the harvesting criteria are that the terminal bud is plump, contains at least 2 lotus root nodes, and is free from pests, diseases, and mechanical damage.

[0017] Based on the above plan, the dormancy period ends in mid-March of the following year. Before the budding period, the lotus root enters a dormant state under the low winter temperatures. By mid-March, dormancy has been largely broken, enzyme activity begins to recover, and nutrients begin to be converted, preparing for budding, but the terminal bud has not yet elongated significantly. Harvesting at this time ensures that the lotus root has the highest vitality and strongest resistance to adverse conditions, is resistant to storage and transportation, and can quickly respond to the temperature rise and germinate after planting.

[0018] In a preferred embodiment, the water level is maintained at 5-10cm from the time the leaves are cut until the lotus root formation stage.

[0019] Based on the above scheme, a shallow water layer of 5-10cm absorbs heat and heats up quickly in sunny weather, which can effectively increase the soil temperature, thereby enhancing the respiration and enzyme activity of roots and underground stems, accelerating metabolism, breaking the dormancy of lateral buds, and stimulating them to sprout and grow into new branches.

[0020] In the preferred embodiment, when planting lotus roots, the top bud of the seed lotus root is inserted obliquely downward into the soil for 10cm, at an angle of 20°-30° to the soil surface. The water level is maintained at 4-6cm during the germination period, 15-20cm during the canopy closure period, and 5-10cm during the tuber formation period.

[0021] Secondly, the present invention provides the application of the method described in any one of the first aspects in reducing the production cost of lotus root seeds.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention employs a combined approach of "leaf removal at the initial stage of canopy closure + double spraying of potassium dihydrogen phosphate during the second canopy closure," applied to specific lotus varieties such as "Donghe Early Lotus," "May Early," and "Elian No. 10." This increases the number of lotus roots per mu (approximately 0.067 hectares) from the conventionally managed 934 to 2735, an increase of 193%. Simultaneously, the yield per mu increases by 657.65 kg. Based on 667 plants per mu and a cost of 3 yuan per kg of lotus root, this translates to a cost saving of 1601 yuan per mu, effectively reversing the traditional "high input, low output" situation in lotus root propagation. Furthermore, the produced lotus roots have fuller terminal buds and shorter internodes, exhibiting a morphology more in line with the requirements for high-quality lotus roots. Leaf removal also clears away flower branches, effectively reducing the number of lotus flowers per unit area and mitigating biological contamination caused by later seed shedding, significantly improving the purity of the lotus roots and the genetic consistency of the variety. Furthermore, the method provided by this invention is highly selective for varieties: "Donghe Early Lotus Root", "May Early", and "Elian No. 10" are sensitive to the reaction, showing a significant increase in the number of seed lotus roots (2500-2800 roots / mu), strong terminal buds, short internodes and no flowering; while varieties such as "Piaohua" have no significant effect due to differences in genetic background (only 1500-1700 roots / mu), indicating that the genetic characteristics of the variety are the key intrinsic factor determining the effectiveness of this technology. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This refers to the lotus root field after the leaves have been removed in this invention.

[0026] Figure 2 This is a comparison diagram of lotus roots with and without leaves removed in this invention.

[0027] Figure 3 It is the lotus root segment grown from the "Donghe Early Lotus Root" selected in this invention.

[0028] Figure 4 It is a lotus root segment grown from the "Elian No. 10" variety selected in this invention.

[0029] Figure 5 It is the lotus root segment grown from the "early May" variety selected in this invention.

[0030] Figure 6 These are lotus root segments grown from the common variety "Piaohua". Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the protection scope of the present invention.

[0032] Example 1: This example provides a method for propagating lotus seedlings based on leaf cutting technology, including the following steps:

[0033] S1. In the early stage of the first closure of the lotus rows, the leaves of the whole field should be cut at a depth of 30cm above the water surface;

[0034] S2. After cutting the leaves, when the lotus roots close up again, spray the leaves with a 0.5% potassium dihydrogen phosphate solution before 9 am or after 4 pm on a sunny day.

[0035] S3. Repeat the spraying with a 0.5% potassium dihydrogen phosphate solution after a 10-day interval;

[0036] The lotus root varieties mentioned are "Donghe Early Lotus Root", "May Early Lotus Root" or "Elian No. 10".

[0037] In step S1, the lotus root leaves are harvested in late May;

[0038] Specifically, in late May, at the initial stage of lotus leaf closure, the leaves should be cut off in the entire field at a depth of about 30cm above the water surface. One month after leaf cutting, when the lotus leaves close again, spray the leaves with 0.5% potassium dihydrogen phosphate before 9 am or after 4 pm on a sunny day. Repeat the spraying once every 10 days to promote the formation of lateral branches of the lotus rhizomes.

[0039] The planting density of lotus root is 1.5-2m row spacing and 1-1.5m plant spacing, with 600-800 kg of seeds per mu and 1-2 seed lotus roots per hole.

[0040] Specifically, when planting lotus roots, the top bud should be angled downwards and inserted into the soil to a depth of about 10cm. The lotus root should be at an angle of 20°-30° to the soil surface, and the lotus root head at the edge of the field should face inwards.

[0041] In addition, maintain a water level of 5-10cm from the time the leaves are cut until the tubers begin to form.

[0042] Specifically, water level management follows the principle of "shallow at the beginning, deep in the middle, and shallow at the end." From planting to the budding stage, maintain a shallow water level of about 5cm; from the emergence of upright leaves to the closing of the canopy, gradually deepen the water layer to 15cm-20cm; after the leaves emerge, lower the water level to 5cm-10cm to facilitate the expansion of lotus roots.

[0043] Harvesting of seed rhizomes: Seed rhizomes are harvested in mid-March of the following year. Seed rhizomes should have plump terminal buds, two or more internodes, and be free from pests, diseases, and serious mechanical damage.

[0044] When planting lotus roots, the top bud of the seed lotus root is inserted obliquely downward into the soil for 10cm, at an angle of 20°-30° to the soil surface. The water level is maintained at 4-6cm during the germination period, 15-20cm during the canopy closure period, and 5-10cm during the tuber formation period.

[0045] The invention will be further explained and illustrated below with reference to experiments:

[0046] 1. Test materials

[0047] The tested varieties were: "Donghe Early Lotus Root", "May Early", and "Elian No. 10".

[0048] Experimental plot: A pond with uniform fertility and convenient irrigation and drainage was selected, with an area of ​​667m². 2 (1 mu).

[0049] Main reagent: Potassium dihydrogen phosphate (analytical grade).

[0050] 2. Leaf cutting experiment

[0051] Experimental group: See Figure 1 Leaf cutting treatment: In the early stage of canopy closure, cut the leaves of the entire field about 30 cm above the water surface;

[0052] Control group: No leaves were cut during the initial stage of canopy closure.

[0053] Experimental results: The seed lotus roots were harvested on March 12 of the following year for yield measurement and evaluation.

[0054] The control group harvested 28 seed lotus plants, with each lotus root weighing 1.58 kg and the total weight of the lotus root being 44.2 kg.

[0055] Referring to Table 1, in the experimental group, after leaf removal treatment, 83 rhizomes were harvested, with a single rhizome weighing 0.65 kg and a total rhizome weight of 54.0 kg (Table 1). It is evident that leaf removal during the canopy closure period inhibited the vegetative growth of the above-ground parts of the lotus root, promoted underground rhizome branching, and significantly increased the number of rhizomes and yield.

[0056] Table 1. Effects of leaf removal treatment on the quality of lotus seedlings

[0057]

[0058] See Figure 2 In the experimental group, although the weight of a single lotus root decreased from 1.58 kg in the conventional treatment to 0.65 kg in the leaf-cutting treatment (a reduction of 58.9%), and the length of the seed lotus root shortened from 113.0 cm to 67.6 cm (a reduction of 40.2%), the number of seed lotus roots per mu (a Chinese unit of area, approximately 0.067 hectares) significantly increased from 934 to 2768. Furthermore, the seed lotus roots treated with leaf cutting had fuller terminal buds and shorter internodes, better meeting the quality requirements and effectively reducing seed lotus root costs. Field observations also revealed that lotus roots treated with leaf cutting had a shorter field growth period and did not flower in the field, while lotus roots treated with conventional treatment had a longer field growth period and produced more flowers after July, easily leading to biological contamination. Therefore, leaf cutting treatment during the lotus root canopy closure period not only significantly increased the number of seed lotus roots and reduced seed lotus root costs but also effectively eliminated the hidden danger of biological contamination caused by lotus seed shedding, improving the purity of the seed lotus roots.

[0059] 3. Potassium dihydrogen phosphate test

[0060] Experimental group: Potassium dihydrogen phosphate treatment. In the early stage of canopy closure, the leaves of the whole field were cut off at a height of about 30 cm above the water surface. When the canopy closed again, 0.5% potassium dihydrogen phosphate was sprayed on the leaves. The 0.5% potassium dihydrogen phosphate was sprayed again after an interval of 7 days.

[0061] Control group: In the early stage of canopy closure, the leaves of the whole field were cut off at a height of about 30 cm above the water surface, and no 0.5% potassium dihydrogen phosphate was sprayed on the leaves.

[0062] Experimental Results: Refer to Table 2. Seed rhizomes were harvested on March 12th of the following year for yield measurement and evaluation. In the control group (without potassium dihydrogen phosphate spraying), 75 seed rhizomes were harvested, with an average rhizome weight of 0.63 kg and a total rhizome weight of 47.3 kg. In the experimental group (sprayed with potassium dihydrogen phosphate), 82 seed rhizomes were harvested, with an average rhizome weight of 0.78 kg and a total rhizome weight of 64.0 kg. It is evident that potassium dihydrogen phosphate treatment enhanced nutrient supply to the lotus plants, promoted underground rhizome branching, and significantly increased the number of seed rhizomes.

[0063] Table 2. Effects of potassium dihydrogen phosphate treatment on the quality of lotus seedlings.

[0064]

[0065] 4. Differences in response of different lotus root varieties to the treatment of "leaf cutting during the canopy closure period + potassium dihydrogen phosphate spraying" Tested varieties: "Donghe Early Lotus", "May Early", "Elian No. 10", "Piaohua";

[0066] Experimental group: Treatment group: All four varieties were treated with the same method of the present invention (i.e., both leaf cutting and spraying with potassium dihydrogen phosphate).

[0067] Leaf cutting (S1): At the beginning of the canopy closure (expected in late May), cut leaves in the entire field at a depth of 30cm above the water surface.

[0068] Spraying (S2, S3): Spray the leaves with a 0.5% potassium dihydrogen phosphate solution one month after leaf cutting and when the canopy closes again, and 10 days later.

[0069] Experimental results: Refer to Table 3. Harvest the lotus roots in the following year during the lotus root harvesting season (mid-March).

[0070] Table 3. Effects of different lotus root varieties on the quality of lotus root seedlings

[0071]

[0072] See Figure 3-6 , Figure 3 The lotus root nodes of the "Donghe Early Lotus Root" variety show a large number of seed lotus roots and plump terminal buds. Figure 4 The lotus root section of "Elian No. 10" Figure 5 The lotus roots harvested in early May all exhibit short internodes and plump terminal buds. Figure 6 These are lotus root segments of the "Floating Flower" variety, exhibiting characteristics of "long internodes and poor quality apical buds," making them unsuitable for lotus root propagation.

[0073] Therefore, the three varieties selected in this invention ("Donghe Early Lotus Root", "May Early", and "Elian No. 10") all achieved an extremely high number of lotus roots per mu (2500-2800 roots / 667m). 2 Furthermore, the morphology of the rhizomes was optimized to achieve an ideal state with shortened internodes and plump apical buds, while effectively suppressing flowering. In stark contrast to the three varieties selected in this invention, the "Floating Flower" variety did not perform well with the same treatment. Its rhizome quantity (1500-1700 rhizomes / 667m²) was significantly reduced. 2 The yield was significantly lower than expected, although the weight of a single rhizome was relatively high (0.9 kg), but the morphology was poor (long internodes, average quality of terminal buds), and flowering was not effectively suppressed. For the varieties selected in this invention ("Donghe Early Lotus Root", "May Early", "Elian No. 10"), this invention not only doubled the number of rhizomes, but also simultaneously optimized the quality of the rhizomes and eliminated the risk of biological contamination caused by flowering and fruiting, achieving a simultaneous improvement in quantity, quality and purity.

[0074] 3. Conclusion

[0075] This invention combines physical methods (leaf cutting) with nutrient regulation (foliar application of phosphorus and potassium fertilizer), and selects specific varieties: "Donghe Early Lotus Root," "May Early," and "Elian No. 10." Leaf cutting and foliar application of 0.5% potassium dihydrogen phosphate at the early stage of lotus canopy closure effectively promote the branching of underground rhizomes, increasing the number of rhizomes per unit area. The potassium dihydrogen phosphate foliar application after leaf cutting increases the weight of individual rhizomes, resulting in better quality rhizomes. The number of rhizomes in the propagation field increased by 1.93 times, and the yield increased by 657.6 kg. Based on 667 plants per mu (approximately 0.067 hectares) and a rhizome price of 3 yuan per kg, the cost of rhizomes per mu is reduced by 1601 yuan, and the risk of biological contamination from seedlings is also reduced.

[0076] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A method for propagating lotus seedlings based on leaf-cutting technology, characterized in that, Includes the following steps: S1. In the early stage of the first closure of the lotus rows, the leaves of the whole field should be cut at a depth of 30cm above the water surface; S2. After cutting the leaves, when the lotus roots close up again, spray the leaves with a 0.5% potassium dihydrogen phosphate solution before 9 am or after 4 pm on a sunny day. S3. Repeat the spraying with a 0.5% potassium dihydrogen phosphate solution after a 10-day interval; The lotus root varieties mentioned are "Donghe Early Lotus Root", "May Early Lotus Root" or "Elian No. 10".

2. The method for propagating lotus seedlings based on leaf-cutting technology according to claim 1, characterized in that: In step S1, the lotus root leaves are harvested in late May.

3. The method for propagating lotus seedlings based on leaf-cutting technology according to claim 1, characterized in that: The planting density of lotus roots is 1.5-2m row spacing and 1-1.5m plant spacing, with 600-800 kg of seeds per mu and 1-2 seed lotus roots per hole.

4. The method for propagating lotus seedlings based on leaf-cutting technology according to claim 1, characterized in that: The lotus root is harvested in mid-March of the following year, and the harvesting criteria are that the terminal bud is plump, contains at least 2 lotus root nodes, and is free from diseases, pests, and mechanical damage.

5. The method for propagating lotus seedlings based on leaf-cutting technology according to claim 1, characterized in that: The water level should be maintained at 5-10cm from the time the leaves are cut until the tubers begin to form.

6. The method for propagating lotus seedlings based on leaf-cutting technology according to claim 1, characterized in that: When planting lotus roots, the top bud of the seed lotus root should be inserted obliquely downwards into the soil for 10cm, at an angle of 20°-30° to the soil surface. During the germination period, the water level should be maintained at 4-6cm, during the canopy closure period, the water level should be maintained at 15-20cm, and during the tuber formation period, the water level should be maintained at 5-10cm.

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