Method for shortening grape breeding period by improving parent culture and grafting propagation

Abstract

The invention relates to a grape crossbreeding technology, in particular to a method for shortening a grape breeding period by improving parent culture and grafting propagation. According to the scheme, a large number of branches with inflorescences (or results) can be rapidly obtained through pre-culture of a primary selection superior line, so that a progeny single plant meeting breeding requirements is selected as an intermediate parent through scientific evaluation of related characters of inflorescences and result conditions; in the next year after the intermediate parents are obtained, a non-intermediate parent single plant in the hybridization nursery is used as a stock, and a strong root system established through multi-year growth of the non-intermediate parent single plant and nutrients accumulated by the non-intermediate parent single plant are used for growth and development of scions of the intermediate parents so as to rapidly clone a large number of the intermediate parents; a large number of well-developed intermediate parent inflorescences are rapidly obtained through inflorescence management and are used for hybridization. According to the method disclosed by the invention, the flowering ability is improved by pre-culturing the primarily selected superior line, the flowering material is rapidly and sufficiently cloned, the inflorescence pollination yield is improved, and the like, so that the multi-generation cross breeding gap is greatly shortened, and the probability of obtaining the high-character excellent grape variety is improved.

Description

Technical Field

[0001] The invention relates to grape hybrid breeding technology, in particular to a method for shortening the grape breeding cycle by improving parent culture and grafting propagation. Background Art

[0002] Grapes are a fruit with significant economic and nutritional value, cultivated extensively around the world. With global climate change, diversifying market demands, and continuous advancements in agricultural technology, cultivating and updating grape varieties with comprehensive and superior traits has become a top priority in grape breeding.

[0003] One of the most prominent challenges facing grape hybridization is the long breeding cycle. To obtain varieties with a combination of superior traits, such as stress resistance, rose fragrance, large grapes, tolerance to low light levels, red skin, and high sugar content, the breeding process often requires complex crossbreeding of multiple generations and multiple parents. Currently, the dominant 'Kyoho' grape variety is derived from the 'Kangko' grape through three generations of hybridization, with the intermediate parents in each generation also derived from complex hybridization. Therefore, to obtain the desired superior variety, multiple generations of hybridization are often required, and each generation of parent selection and offspring generation requires a complete breeding cycle, averaging 15-20 years to complete.

[0004] Generally speaking, a complete grape hybrid breeding cycle mainly includes the following important links:

[0005] (1) Select parents: determine the parents.

[0006] (2) Hybrid seed harvest: Collect pollen from the male parent, emasculate the female parent, pollinate, and harvest the hybrid seed in the same year;

[0007] (3) Hybrid first generation seedlings: seed germination, sowing, seedling transplanting, and harvesting the seedlings in the same year;

[0008] (4) Planting: Plant the annual hybrid seedlings in the hybrid nursery and manage them in the usual way.

[0009] (5) Determine the primary superior lines: After 3-4 years of fruiting, select individual plants with excellent target traits based on trait evaluation data, which are the primary superior lines. Mature branches of the primary superior lines are collected and buried in the soil for storage.

[0010] (6) Superior line propagation: Cut mature branches into sections, propagate seedlings by cuttings, and harvest in autumn.

[0011] (7) Planting: Plant a certain number of one-year-old primary selected superior line seedlings in the secondary selection plot and manage them in the usual way.

[0012] (8) Determine the superior lines after reselection: After 3-4 years of fruiting, determine the superior lines after reselection based on the evaluation of trait consistency and stability.

[0013] (9) Superior line propagation: Cut mature branches into sections and propagate a large number of seedlings through cuttings, which will be harvested in autumn.

[0014] (10) Regional trials: superior seedlings are planted in different ecological areas for testing, and the results are evaluated continuously for three years.

[0015] (11) Variety approval and other subsequent related work.

[0016] In the above technical solution, after obtaining a primary selected superior line that meets the breeding objectives, asexual propagation is required to obtain sufficient secondary selected superior lines as soon as possible. Only after these lines can stably flower can the next step of hybridization breeding be carried out. The process from obtaining the primary selected superior line to obtaining the expanded secondary selected superior line and then achieving stable flowering in the secondary selected superior line typically takes 4-6 years. Shortening the time it takes for high-quality hybrid offspring to serve as intermediate parents for the next generation of breeding has become a key factor restricting the rapid multi-generational breeding of grapes. Summary of the Invention

[0017] (1) Technical issues to be resolved

[0018] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for shortening the grape breeding cycle by improving parent culture and grafting propagation. The method is suitable for processing hybrid seedlings produced by grape hybridization, so that after obtaining the first-generation hybrid seedlings, sufficient primary selected superior line expansion seedlings can be quickly produced to participate in subsequent hybrid breeding. Compared with traditional methods, the breeding cycle can be significantly shortened, solving the technical problems of the existing grape breeding cycle being too long and the variety production speed being too slow.

[0019] (2) Technical solution

[0020] The present invention provides a method for shortening the grape breeding cycle by improving parent culture and grafting propagation, which comprises:

[0021] S1. Pre-cultivation and selection of superior lines

[0022] In the first year, the pre-selected superior hybrid seedlings were planted in the hybrid nursery and managed using a V-shaped frame with a single stem and single arm. When the new shoots grew to 30-40 cm in length, a strong new shoot was selected from each plant and set as the main stem. When the new shoots grew to 100-120 cm, the tops were pinched and the new shoots were tied 48-52 cm above the ground along the planting row to promote the germination and development of secondary shoots. The secondary shoots were pinched when they had 4 leaves. After the leaves fell in late autumn, the secondary shoots were pruned with two buds left.

[0023] In the second year, when the plant has inflorescences, pinch off the new shoots when they have 5-7 leaves, and pinch off the secondary shoots with one leaf, and tie the new shoots horizontally or with the tips facing down to inhibit vegetative growth; after flowering, fertilize each plant to promote the initial differentiation of flower buds; after the fruit swells, fertilize each plant to promote the differentiation of flower organs; after the leaves fall in late autumn, prune back to keep two buds;

[0024] In the third year, the operation of the second year is repeated (in the third year, usually those individual plants that did not produce inflorescences (or fruits) in the second year also begin to bloom and bear fruit);

[0025] S2. Screening of intermediate parents

[0026] When the plant has inflorescence, relevant traits are scientifically evaluated to select offspring plants that meet breeding requirements and determine them as intermediate parents. After the plant is determined to be used as the intermediate parent, it is pruned after the leaves fall in late autumn, retaining two buds. The pruned branches are stored at a low temperature (4-6°C) until the following spring for use in scion production.

[0027] S3, rapid cloning of intermediate parents

[0028] In the spring of the following year, after the grapes sprout, the refrigerated branches are taken out, the branches with buds are selected, and they are pruned into segments with single buds, which are then fully watered and used as scions.

[0029] Select plants adjacent to the intermediate parent plant, cut them into rootstocks, make two incisions on the end surface of each rootstock, insert a scion with a wedge-shaped end into each incision, seal the cut surface of the rootstock, the incision, and the wedge-shaped surface of the scion with a splicing tape, exposing the bud of the scion, water the rootstock, and manage the original mother plant used as the intermediate parent in the same manner as usual;

[0030] S4. Inflorescence development management

[0031] After the scion sprouts, fertilize the rootstock to promote the growth of scion leaves. When the scion shoots grow to 20 cm, fertilize again to promote the growth of new shoots and the appearance of inflorescences.

[0032] When treating the scion of a stock, keep the scion with inflorescence on the stock, and pinch off the 6-7 leaves above the flower, and keep the side shoots with 1 leaf and pinch them repeatedly; for the scion without inflorescence on the stock, pinch off the top of the 5th leaf, and keep only the side shoot near the top after the side shoots sprout; if both scions on the stock have no inflorescence, keep the scion with stronger growth potential (remove the scion with weaker growth potential), pinch off the top of the 5th leaf, and keep only the side shoot near the top after the side shoots sprout;

[0033] Pinch off the 4-5 leaves on the nutrient branches without inflorescences on the original mother plant to promote the development of secondary shoots. After the secondary shoots grow to the appearance of inflorescences, pinch off the 4-5 leaves above the flowers and repeatedly remove the secondary shoots.

[0034] One week before the flowering of the rootstock, scion and original mother plant, spray the leaves with fertilizers and growth regulators that promote the healthy development of floral organs to prepare for hybridization;

[0035] S5. Harvesting hybrid seeds

[0036] When the flower caps of single flowers on the inflorescence fall off, prepare for hybridization; bag the hybrid inflorescences and harvest the seeds after the fruits are ripe.

[0037] According to a preferred embodiment of the present invention, in S1, in the first year, the pre-selected superior hybrid seedlings are planted in the hybrid nursery with a plant spacing of 0.7±0.1m×1.5±0.2m, and managed with a single stem and single arm of a V-shaped frame; after the main trunk is determined, a water-soluble compound fertilizer with N:P:K=3:1:1 is applied to promote rapid growth of the plants; when the new shoots grow to 100-120cm, they are topped to promote the germination of lateral shoots, and the new shoots are pulled and tied from 50cm above the ground along the planting row direction to promote the germination and development of lateral shoots; when the lateral shoots grow to 4 leaves, they are topped; after the leaves fall in late autumn, the lateral shoots are pruned to leave two buds.

[0038] According to a preferred embodiment of the present invention, in S1, in the second year, when the plant has inflorescences, the new shoots are topped when they grow to 5-7 leaves, the side shoots are topped while leaving one leaf, and the new shoots are tied horizontally or with the tips facing down to inhibit vegetative growth; after flowering, a water-soluble fertilizer with N:P:K=1:2:3 is applied to the roots of each plant, and 0.2% boric acid + 0.1% zinc sulfate is sprayed on the leaves to promote the initial differentiation of flower buds; after the fruit swells, a water-soluble fertilizer with N:P:K=1:2:3 is applied to the roots of each plant, and 0.3% boric acid is sprayed on the leaves to promote the differentiation of flower organs; after the leaves fall in late autumn, pruning is performed with two buds retained.

[0039] According to a preferred embodiment of the present invention, in S2, when screening the intermediate parent plants, the relevant traits include but are not limited to fruit size, fruit uniformity, skin-residue ratio, fruit powder thickness, peel color, peeling difficulty, seed coat hardness, flesh crispness, acidity, soluble solids content, allergen content, aromatic substance types, fragrance, number of single seeds, phenological period parameters, secondary fruiting rate, fruit cracking rate after rain, sunburn sensitivity, chilling sensitivity, disease infectivity, storage and transportation resistance, new shoot internode length, and flower bud differentiation stability, or a combination of several of them; when screening the intermediate parent plants, inflorescences or fruits usually appear in the third year to facilitate scientific evaluation of the relevant traits; if no inflorescences or fruits appear in the third year, the evaluation is delayed for one year; if certain traits need to be observed for many consecutive years, the cultivation and management measures of the second or third year of step S1 are repeated the following year, and observation and screening are carried out until the target plants are screened out.

[0040] According to a preferred embodiment of the present invention, in S3, after the grapes sprout in the spring of the following year, the following operations are performed in sequence:

[0041] S31, taking out the refrigerated branches, selecting the branches with buds at the base, cutting the branches into segments with single buds, soaking them in sterile water to fully absorb water, and obtaining scions;

[0042] S32, selecting a plant adjacent to the middle parent plant, cutting its trunk horizontally 35-45 cm above the ground to form a rootstock;

[0043] S33: Make two vertical cuts 5-8 mm wide and 4-5 cm deep on the end of the stock.

[0044] S34, with the scion eye as the front, make oblique cuts on the left and right sides of the scion to form wedge-shaped surfaces, with the length of the wedge-shaped surface matching the incision depth;

[0045] S35, inserting the wedge-shaped surface of the scion into the incision of the stock, inserting a scion into each of the two incisions of one stock, and sealing the incision of the stock, the end surface of the stock, and the wedge-shaped surface of the scion with grafting tape, leaving only the bud of the scion exposed;

[0046] S36. Water the roots of the rootstock to keep the soil moist; manage the original mother plant used as the intermediate parent as usual.

[0047] According to a preferred embodiment of the present invention, the operation method of S31 is as follows: taking out the refrigerated branches, selecting the branches with buds at the base, cutting the branches into segments with single buds, leaving 1.4-1.6 cm (preferably 1.5 cm) above the buds and 5-8 cm below, soaking them in distilled water for 12 hours to fully absorb water, and obtaining scions;

[0048] The operation method of S32 is as follows: select a plant adjacent to the intermediate parent plant, cut its trunk 40 cm above the ground to form a rootstock; this can fully utilize the obtained hybrid population, and use the strong root system and accumulated nutrients of the non-intermediate parent plant (rootstock) in the hybrid nursery that has grown for many years for the growth and development of the scion, thereby ensuring the good development of the scion inflorescence;

[0049] The operation method of S33 is as follows: remove a circle of bark below the end of the rootstock (to facilitate the use of grafting tape to fully wrap and seal the grafting incision and the end of the rootstock), and make two vertical incisions 5-8mm wide and 4-5cm deep on the end of the rootstock. Two incisions can be grafted with two scions, which can quickly increase the number of clones of the middle parent;

[0050] The operation method of S34 is: with the bud of the scion as the front, make bevel cuts on both sides of the scion to form wedge-shaped surfaces. The length of the wedge surface matches the incision depth, which is 4-5cm. Make sure the wedge surface is smooth to facilitate effective healing of the grafting site.

[0051] The operation method of S35 is: insert the wedge-shaped surface of the scion into the cut of the rootstock, keep at least one side of the cambium of the rootstock and the scion aligned, and seal the rootstock cut, the end face of the rootstock and the wedge-shaped surface of the scion with grafting tape, leaving only the bud of the scion exposed.

[0052] According to a preferred embodiment of the present invention, in S4, after the scion sprouts, a water-soluble fertilizer with N:P:K=3:1:1 (or potassium dihydrogen phosphate water-soluble fertilizer) is applied to the root of the stock to promote the growth of scion leaves. When the scion shoot grows to 20 cm, a water-soluble fertilizer with N:P:K=1:1:1 is applied to the root again to promote the growth of the new shoot and the appearance of the inflorescence.

[0053] If the secondary shoots grow and inflorescences appear, pinch off the top 4-5 leaves above the flowers and repeatedly remove the secondary secondary shoots (to ensure the good development of the inflorescences and improve the pollination rate of the inflorescences);

[0054] One week before the flowering of the rootstock, scion and original mother plant, spray the leaves with 0.2% boric acid + 0.1% zinc sulfate + 100 mg / L brassinolide to promote the healthy development of floral organs and prepare for hybridization.

[0055] According to a preferred embodiment of the present invention, in S5, hybridization is started when the flower cap of a single flower on the inflorescence falls off;

[0056] If the middle parent is used as the male parent, the male parent inflorescence is collected for pollen collection and smeared on the female parent inflorescence with the stamens removed; if the middle parent is used as the female parent, the female parent inflorescence is artificially emasculated, the spike is bagged, and after the stigma secretes mucus, the male parent pollen is smeared on the stigma;

[0057] After hybridization, the hybrid inflorescences are bagged and marked, and covered with bird-proof bags. After the fruits are ripe, the seeds are harvested.

[0058] (3) Beneficial effects

[0059] The method provided by the present invention is applicable to the process from obtaining hybrid first-generation seedlings to obtaining a large number of propagation materials to participate in hybrid breeding; the scheme pre-cultivates a large number of branches with inflorescences (or fruits) through the pre-selection of superior lines, thereby scientifically evaluating the relevant characteristics of the inflorescences and fruits to select offspring single plants that meet the breeding requirements as intermediate parents; then, in the second year after the intermediate parents are obtained, by using non-intermediate parent single plants in the hybrid garden as rootstocks, the strong root system established by the multi-year growth and the accumulated nutrients are used for the growth and development of the intermediate parent scion, so as to quickly and massively clone the intermediate parents, and then combine with the original mother plant used as the intermediate parent (the intermediate parent can also be provided), a large base number of intermediate parent single plants can be obtained; in the process of inflorescence development management, through reasonable fertilization to promote growth and pinching and other treatments, a large number of well-developed intermediate parent inflorescences are obtained within one year for hybridization.

[0060] The method provided by the present invention can quickly obtain a large number of well-developed and hybridizable intermediate parent inflorescences for hybridization within one year after obtaining the initially selected superior lines that meet the requirements, and can significantly shorten the breeding cycle of steps (5) to (8) in the traditional grape breeding scheme, and can shorten the breeding time of the traditional process from about 5-6 years (or even longer) to one year; at the same time, the cutting propagation of the reselected superior lines in the traditional grape breeding scheme usually requires the cutting branch segment to contain at least two buds to ensure the survival rate of the seedlings, which not only has a long cycle, slow propagation speed and low survival rate; while the present invention uses adjacent non-intermediate parent single plants in the hybridization garden as rootstocks, and the non-intermediate parent single plants have been planted in the hybridization garden for 3-4 years. Two scions are grafted onto each rootstock, and each scion only needs to have one bud to utilize the strong root system established by the rootstock for many years and the nutrients accumulated therein for growth, with a high survival rate and a fast growth rate. In the year of grafting, twice the amount of propagation material and well-developed inflorescences of conventional breeding can be provided at one time for hybridization to produce hybrid seeds.

[0061] The method of the present invention rapidly obtains a large amount of high-fertility materials for hybrid breeding by pre-cultivating primary selected superior lines to improve flowering ability, quickly cloning flowering materials in sufficient quantities, and improving the inflorescence pollination yield, thereby significantly shortening the gaps between multiple generations of hybrid breeding and greatly increasing the probability of successfully obtaining high-trait and excellent grape varieties. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a time sequence diagram for shortening the multi-generation hybrid breeding cycle of grapes according to the present invention.

[0063] Figure 2 This is a schematic diagram of the screening and rapid breeding application of intermediate parents;

[0064] A: Based on the results of tree survey and fruit trait evaluation, the target superior line is screened from the hybrid offspring and determined as the intermediate parent. Its one-year-old branches are collected in the same year and stored at 4℃; B: After budding in the spring of the following year, a certain number of hybrid plants adjacent to the intermediate parent mother plant are selected, and the tree trunks more than 40-50 cm are cut off to use as rootstocks; C: The stored intermediate parent branches are taken out to make scions, which are grafted onto adjacent rootstocks, with two scions per rootstock; D: After the scion reveals the inflorescence, the scion shoot with the inflorescence is retained, and the scion shoot without the inflorescence is pinched on 4-5 leaves. When both scions on a rootstock have no inflorescence, the strong shoot is retained and pinched on 4-5 leaves; E: The side shoots germinate and carry inflorescences, which can be used for pollen collection or pollen receptors. DETAILED DESCRIPTION

[0065] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0066] Example 1

[0067] The method of this embodiment can quickly obtain a large amount of propagation materials to participate in the hybrid breeding process after obtaining the first generation hybrid seedlings, and specifically includes the following steps:

[0068] (1) Pre-cultivation and selection of superior lines

[0069] In the first year, the hybrid seedlings were transplanted into the hybrid nursery with a row spacing of 0.7m×1.5m, and managed with a single stem and single arm of a V-shaped frame; when the new shoots grew to 30-40cm in length, a strong new shoot was selected from each plant and set as the main stem; after the stem was set, a water-soluble compound fertilizer with N:P:K=3:1:1 was applied, with a dosage of about 15-20g per plant each time, once every 10 days, for 3 times to promote rapid growth of the plants; when they grew to 100-120cm, they were pinched to promote the germination of lateral shoots; the new shoots were pulled and tied from 50cm above the ground along the planting row direction to promote the development of lateral shoots; when the lateral shoots grew to 4 leaves, they were pinched, and if there were secondary lateral shoots, 1 leaf was left and pinched; after the leaves fell in late autumn, the lateral shoots were pruned, leaving two buds.

[0070] In the second year, when the plant has inflorescences, the new shoots can be pinched when they grow to 5-7 leaves, and the side shoots should be pinched with one leaf left, and the new shoots should be tied horizontally or with the tips facing down to inhibit vegetative growth; after flowering, apply about 20g of water-soluble fertilizer with N:P:K=1:2:3 to each root of each plant, spray 0.2% boric acid + 0.1% zinc sulfate on the leaves and spray again after 10 days to promote the initial differentiation of flower buds; after the fruit swells, apply about 20g of water-soluble fertilizer with N:P:K=1:2:3 to each root of each plant, spray 0.3% boric acid on the leaves and spray again after 10 days to promote the differentiation of floral organs; after the leaves fall in late autumn, keep two buds and prune.

[0071] In the third year, the operation of year 2 is repeated. In the third year, usually those individual plants that did not produce inflorescences (or fruits) in the second year also begin to bloom and bear fruit.

[0072] (2) Screening of intermediate parents

[0073] In the third year (if no flowers appear, continue to the next year), conduct a scientific evaluation of relevant traits in the corresponding period, select offspring plants that meet the breeding requirements, and determine them as intermediate parents. Relevant traits include but are not limited to fruit size, fruit uniformity, skin-to-residue ratio, fruit powder thickness, peel color, peeling difficulty, seed coat hardness, flesh crispness, acidity, soluble solids content, allergen content, aromatic substance types, fragrance, number of seeds per seed, phenological parameters, secondary fruiting rate, fruit cracking rate after rain, sunburn sensitivity, cold damage sensitivity, disease infection (resistance), storage and transportation resistance, new shoot internode length, and flower bud differentiation stability, or a combination of several of them. If certain traits need to be observed for many consecutive years, repeat the cultivation and management measures of the third year the following year, and observe and screen until the target plants are selected.

[0074] After determining the single plant to be used as the intermediate parent, prune it after the leaves fall in late autumn, leaving two buds, and store the pruned branches at a low temperature of 4°C until the following spring.

[0075] (3) Rapid cloning of intermediate parents

[0076] In the spring of the following year, after the grapes sprouted, the following operations were performed (such as Figure 2 shown):

[0077] (1) Scion preparation: Take out the cold-stored branches, and give priority to branches with buds at the base of the branches. Cut the branches into segments with single buds, leaving 1.5 cm above the bud and 5-8 cm below. Soak them in distilled water for 12 hours to allow them to fully absorb water.

[0078] (2) Rootstock preparation: To fully utilize the hybrid population obtained, select adjacent plants (such as Figure 2 A), cut the trunk horizontally at 40 cm above the ground to serve as the rootstock (such as Figure 2 B). This allows the strong root system and accumulated nutrients of the rootstock to be used for the growth and development of the scion, ensuring the good development of the scion inflorescence.

[0079] (3) Rootstock splitting: To facilitate the use of grafting tape to seal the grafting point, it is necessary to remove a circle of bark below the end of the rootstock and make two vertical splits 5-8 mm wide and 4-5 cm deep on both sides of the cross section. The two cuts can be used to insert two scions.

[0080] (4) Making the scion: With the bud of the scion as the front, cut the scion obliquely on its left and right sides to form a wedge surface. The wedge surface is 4-5 cm long and must be smooth so that the grafting site can heal effectively.

[0081] (5) Grafting: Insert the scion into the cut of the stock and align the cambium (cells) on at least one side of the cut of the scion and the stock. Insert one scion into each cut and graft two scions onto one stock (e.g. Figure 2 C) Finally, seal the cut and the cut surfaces of the stock and scion with grafting tape, leaving only the scion bud exposed.

[0082] (6) After grafting: Water the rootstock to keep the soil moist; manage the original mother plant used as the intermediate parent in the usual way.

[0083] (4) Managing inflorescence development

[0084] After the scion sprouts, dissolve a water-soluble fertilizer with an N:P:K ratio of 3:1:1 and apply it to the rootstock base at a rate of 40 grams per plant to promote rapid leaf growth and enhance photosynthetic efficiency. When the new shoots reach 20 cm, dissolve a water-soluble fertilizer with an N:P:K ratio of 1:1:1 and apply it to the rootstock base at a rate of 40 grams per plant to promote new shoot growth and the appearance of inflorescences. Leave the scion with inflorescence on the rootstock and pinch off the 6-7 leaves above the flower. Leave the secondary shoots with 1 leaf and pinch off the top repeatedly. For the nutrient branches on the stock that do not carry inflorescences, pinch off the top of the 5th leaf. After the lateral shoots germinate, only one lateral shoot near the top is retained. If the lateral shoots grow and inflorescences appear, pinch off the top of the 4-5 leaves above the flower, and repeatedly remove the secondary lateral shoots. If both scions on the stock do not have inflorescences, retain the scion with stronger growth potential, pinch off the top of the 5th leaf. After the lateral shoots germinate, only one lateral shoot near the top is retained. If the lateral shoots grow and inflorescences appear, pinch off the top of the 4-5 leaves above the flower, and repeatedly remove the secondary lateral shoots. For the developmental branches (nutrient branches without inflorescences) on the original mother plant, pinch off the top of the 4-5 leaves to promote the development of lateral shoots. After the lateral shoots grow until the inflorescences appear, pinch off the top of the 4-5 leaves above the flower, and repeatedly remove the secondary lateral shoots. The lateral shoots germinate and carry inflorescences, which can be used for pollen collection or pollen receptors (such as Figure 2 D and E).

[0085] About one week before flowering of the rootstock, scion and original mother plant, spray the leaves with 0.2% boric acid + 0.1% zinc sulfate + 100 mg / L brassinolide to promote the healthy development of floral organs.

[0086] (5) Hybridization and Harvesting Hybrid Seeds

[0087] When the caps of individual flowers on the inflorescence fall off, hybridization begins. If the intermediate parent is used as the male parent, pollen is collected from the inflorescence and applied to the female parent's inflorescence after the stamens have been removed. If the intermediate parent is used as the female parent, the inflorescence is manually emasculated, the spike is bagged, and after the stigma secretes mucus, pollen from the male parent is applied to the stigma. After hybridization, the hybrid inflorescence is bagged, marked, and covered with a bird-proof bag. When the fruit matures, the seeds are harvested.

[0088] like Figure 1 As shown, compared with the traditional grape hybrid breeding method, this embodiment can quickly obtain a large number of well-developed intermediate parent inflorescences that can be used for hybridization within one year after obtaining the primary selected superior lines that meet the requirements, which can significantly shorten the breeding cycle of steps (5) to (8) in the traditional grape breeding program, and can shorten the traditional breeding time of this process from about 5 years to one year, and the entire breeding cycle can be shortened by more than 40%.

[0089] The features and effects of the present invention are further described below in conjunction with application examples of the present invention.

[0090] Application Example 1

[0091] The grape breeding goal of this example is to produce a rose-scented grape variety with red color, large berries, crisp flesh, and high resistance to downy mildew. The entire breeding process is as follows:

[0092] 2015: The red-skinned, crisp-fleshed, large-grained 'Red Globe' grape was used as the female parent, and the red, rose-scented 'Rose Fragrance' grape was used as the male parent for hybridization. 21 clusters of hybrid fruit were obtained that year and stored at 4°C.

[0093] 2016: 2,520 hybrid seeds were obtained from grape berries. Soak the seeds in clean water for 12 hours, discard any floating, shrunken seeds, and then soak them in carbendazim for one hour. Drain the seeds and spread them flat on a damp towel, then cover them with another damp towel. Maintain the ambient temperature at around 22°C to promote germination. Germinated seeds were selected daily and sown on a well-absorbent seedling medium. This was then covered with vermiculite and sprayed with water. The temperature was then maintained at around 25°C to promote rooting and germination. When the seedlings reached 5-8 cm in height, they were transplanted to the field on a cloudy day, with a row spacing of 0.1 m x 0.5 m. After transplanting, they were watered thoroughly. When the seedlings reached 80 cm, the tips were clipped to promote trunk maturity. After leaf fall in late autumn, the first-generation hybrid seedlings were harvested and buried in a 1-meter-deep storage trench to overwinter.

[0094] The following is performed with reference to the scheme of the present invention:

[0095] 2017: The hybrid seedlings mentioned above were taken out from the storage ditch and planted in the hybrid nursery with a plant spacing of 0.7m×1.5m. V-shaped frame single-stem single-arm management was used; when the new shoots grew to 30-40cm long, one strong new shoot was selected for each plant and set as the main trunk; after the trunk was set, potassium dihydrogen phosphate (N:P:K≈3:1:1) was dissolved in water and applied to the roots of the plants, about 20g per plant each time, once every 10 days, for 3 times; when the new shoots grew to about 120cm, they were topped; the new shoots were pulled and tied from 50cm above the ground along the planting row direction, the lateral shoots were topped when they grew to 4 leaves, and the secondary lateral shoots were topped with 1 leaf; after the leaves fell in late autumn, the lateral shoots were pruned with two buds.

[0096] 2018: When inflorescences appear in nearly one-third of the plants, pinch off new shoots when they have 5-7 leaves. Pinch off secondary shoots, leaving one leaf. Tie new shoots horizontally or with the tips pointing downward. After flowering, apply about 20g of a water-soluble fertilizer with a N:P:K ratio of 1:2:3 to the roots of each plant. Spray the leaves with 0.2% boric acid + 0.1% zinc sulfate, and spray again after 10 days. After fruit enlargement, apply about 20g of a water-soluble fertilizer with a N:P:K ratio of 1:2:3 to the roots of each plant. Spray the leaves with 0.3% boric acid, and spray again after 10 days to promote floral differentiation. Prune after leaf drop in late autumn, leaving two buds.

[0097] 2019: Strict management was implemented according to the 2018 cultivation practices, and by July-October, nearly all individual plants had borne fruit. Field surveys and fruit quality evaluations identified the superior strain '16-13-2'. This strain features large berries, red skin, crisp flesh, high soluble solids content, and a rose fragrance, but is susceptible to downy mildew. It will subsequently be used as an intermediate parent (as the male parent) in a hybridization with the highly downy mildew-resistant, crisp-fleshed, blue-skinned, male-sterile '4-19-2' (using the 'Moldova' grape as the male parent and the 'Red Globe' grape, with its red skin, crisp flesh, and large berries, as the female parent). After leaf drop in autumn, '16-3-2' was pruned to two buds, and the pruned branches were stored in a 4°C artificial climate chamber.

[0098] 2020: After bud break in spring, the following grafting process will be carried out:

[0099] Remove the refrigerated '16-3-2' branches, prioritizing the buds at the base of the branches. Cut the branches into segments with single buds, leaving 1.5 cm above the bud and 5-8 cm below. Soak in distilled water for 12 hours to allow for full water absorption. Select plants adjacent to '16-3-2' in the hybrid nursery (such as '16-3-1', '16-3-3', etc.), cut the main trunk horizontally at 40 cm above the ground, and use them as rootstocks. Remove the bark below the end of the rootstock and make two vertical cuts 5-8 mm wide and 4-5 cm deep on either side of the cross section. With the direction of the scion's bud as the front, cut the scion diagonally on both sides to form wedges. The wedges are 4-5 cm long and smooth to ensure effective healing of the grafting site. Insert the scion into the rootstock cut, aligning it with the cambium. Wrap the cut and the cut surfaces of the rootstock and scion with grafting tape to seal the cut, leaving only the scion's bud exposed. After grafting, water the rootstock until the soil is moist; the original mother plant '16-3-2' is managed according to the conventional method.

[0100] After the scion sprouts, apply potassium dihydrogen phosphate water-soluble fertilizer to the rootstock root, 40g per plant. When the new shoot grows to 20 cm, apply a water-soluble fertilizer with N:P:K=1:1:1 to the rootstock root, 40g per plant. Keep the new shoots of the scion with inflorescence on the grafted tree, and pinch off 6-7 leaves above the flower, and pinch off the side shoots while leaving 1 leaf; pinch off the nutrient branches without inflorescence above the 5th leaf, and keep only one side shoot near the top after the side shoots germinate; if the side shoot grows and inflorescence appears, pinch off 5 leaves above the flower, and repeatedly remove the secondary side shoots; if both scions on the grafted tree have no inflorescence, keep only the nutrient branches with vigorous growth, pinch off above the 5th leaf, and keep only one side shoot near the top after the side shoots germinate; if the side shoot grows and inflorescence appears, pinch off 5 leaves above the flower, and repeatedly remove the secondary side shoots; pinch off the developmental branches (nutrient branches without inflorescence) on the original mother plant while leaving 5 leaves to promote the development of side shoots. After the side shoots grow until the inflorescence appears, pinch off 5 leaves above the flower, and repeatedly remove the secondary side shoots. About one week before flowering on the intermediate parent scion and the original mother plant, spray the leaves with 0.2% boric acid + 0.1% zinc sulfate + 100 mg / L brassinolide to promote the healthy development of floral organs.

[0101] When sporadic blooms are seen on the inflorescences, collect the inflorescences of '16-3-2' and bring them back to the laboratory to collect pollen. Apply the pollen of '16-3-2' to the flowering inflorescences of the male-sterile '4-19-2'. After application, bag the inflorescences and tie the branches to the culture rack. Mark the hybrid inflorescences and cover them with bird-proof bags. Harvest the seeds after the fruits mature.

[0102] Application Example 2

[0103] The breeding goal of this embodiment is to develop a grape variety with high resistance to downy mildew, firm flesh, high sugar content, and good storage and transportation resistance.

[0104] 2014: Hybridization was carried out using the 'Moldova' grape, which is highly resistant to downy mildew and has good storage and transportation properties, as the male parent and the 'Red Globe' grape, which has red skin, crisp flesh and large grains, as the female parent. Fifteen clusters of hybrid fruit were obtained that year and stored at 4°C.

[0105] 2015: 1,881 hybrid seeds were obtained from grape berries. Soak the seeds in clean water for 12 hours, discard any floating, shrunken seeds, and then soak them in carbendazim for one hour. Drain the seeds and spread them flat on a damp towel, then cover them with another damp towel. Maintain the ambient temperature at around 22°C to promote germination. Germinated seeds were selected daily and sown on a well-absorbent seedling medium. This was then covered with vermiculite and sprayed with water. The medium was then covered with film to retain moisture. The temperature was maintained at around 25°C to promote rooting and germination. When the seedlings reached 5-8 cm in height, they were transplanted to the field on a cloudy day, with a spacing of 0.1 m x 0.5 m between rows and plants. After transplanting, they were watered thoroughly. When the seedlings reached 80 cm, the tips were trimmed to promote trunk maturity. After leaf fall in late autumn, the first-generation hybrid seedlings were harvested and buried in a 1-meter-deep storage trench to overwinter.

[0106] The following is performed with reference to the scheme of the present invention:

[0107] 2016: The hybrid seedlings mentioned above were taken out from the storage ditch and planted in the open-field hybrid nursery with a row spacing of 0.7m×1.5m. They were managed with a single-stem and single-arm V-frame. When the new shoots grew to 30-40cm in length, one strong new shoot was selected from each plant and set as the main trunk. After the trunk was set, potassium dihydrogen phosphate (N:P:K≈3:1:1) was dissolved in water and applied to the roots of the plants, about 20g per plant per time, once every 10 days, for 3 times. When they grew to about 120cm, they were topped. The new shoots were pulled and tied from 50cm above the ground along the planting row direction. The lateral shoots were topped when they grew to 4 leaves, and the secondary lateral shoots were topped with 1 leaf. After the leaves fell in late autumn, the lateral shoots were pruned with two buds.

[0108] 2017: Inflorescences appeared on a small number of plants that year. When the new shoots grew to 5-7 leaves, they were pinched off. The secondary shoots were pinched off with one leaf left, and the new shoots were tied horizontally or with the tips facing down. After flowering, about 20g of water-soluble fertilizer with N:P:K≈1:2:3 was applied to the roots of each plant, and 0.2% boric acid + 0.1% zinc sulfate was sprayed on the leaves, and sprayed again after 10 days. After the fruit swelled, about 20g of water-soluble fertilizer with N:P:K≈1:2:3 was applied to the roots of each plant, and 0.3% boric acid was sprayed on the leaves, and sprayed again after 10 days. After the leaves fell in late autumn, pruning was retained with two buds.

[0109] 2018: Strict management was implemented according to the 2018 cultivation practices. By July–October 2018, 80% of the plants were bearing fruit. During the rainy season, the leaves and fruits of the plants were surveyed for downy mildew. Fruit characteristics were scientifically evaluated, and the primary superior line, '4-19-2', was selected. This superior line is highly resistant to downy mildew, has dark-blue fruit skin, and crisp flesh. Furthermore, its flowers are male-sterile, making it an ideal hybrid parent. Therefore, it was selected as the intermediate parent for hybridization with a rose-scented, early-maturing line. After leaf drop in autumn, '4-19-2' was pruned to two buds, and the pruned branches were stored in a 4°C artificial climate chamber.

[0110] 2019: After bud break in spring, remove '4-19-2' branches from cold storage. Preferentially select the bud at the base of the branch and cut the branch into segments with a single bud, leaving 1.5 cm above the bud and 5-8 cm below. Soak in distilled water for 12 hours to allow for full hydration. Select several plants adjacent to '4-19-2' in the hybrid nursery (e.g., '4-19-1', '4-19-3', '4-19-4', etc.), cut their trunks horizontally at 40 cm above the ground, and use them as rootstocks. Remove the bark below the rootstock end and make two vertical incisions 5-8 mm thick and 4-5 cm deep on either side of the cross section. With the bud at the front, bevel the scion on both sides to form a wedge, 4-5 cm long, and ensure it is smooth to allow for effective healing of the grafting site. Insert the scion into the cut of the rootstock, ensuring that the cambium on at least one side is aligned. Wrap the cut and the cut surfaces of the rootstock and scion with grafting tape to seal it, leaving only the scion bud exposed. After grafting, water the rootstock until the soil is moist. Manage the original mother plant '4-19-2' as usual.

[0111] After the scion sprouts, use potassium dihydrogen phosphate dissolved in water and apply it to the root of the stock, with a fertilizer amount of 40g per plant. When the new shoot grows to 20 cm, use a water-soluble fertilizer with N:P:K=1:1:1 and apply it to the root of the stock, with a fertilizer amount of 40g per plant. Keep the scion shoot with inflorescence on the grafted tree, and pinch it 6-7 leaves above the flower, and pinch the side shoots with 1 leaf; pinch the nutrient branches without inflorescence above the 5th leaf, and after the side shoots sprout, only keep one side shoot near the top; if the side shoot grows and inflorescence appears, pinch it 5 leaves above the flower, and repeatedly remove the secondary side shoots; if both scions on the grafted tree have no inflorescence, only keep the nutrient branches with strong growth potential, pinch it above the 5th leaf, and after the side shoots sprout, only keep one side shoot near the top; if the side shoot grows and inflorescence appears, pinch it 5 leaves above the flower, and repeatedly remove the secondary side shoots.

[0112] Pinch off the developmental branches (nutrient branches without inflorescences) on the original mother plant while leaving 5 leaves to promote the development of lateral shoots. After the lateral shoots grow to the appearance of inflorescences, pinch off 5 leaves on the flowers and repeatedly remove the secondary lateral shoots. About 1 week before the flowering of the above-mentioned scion and the original mother plant, spray the leaves with 0.2% boric acid + 0.1% zinc sulfate + 100 mg / L brassinolide.

[0113] When a few flowers begin to bloom on the inflorescence, bag the inflorescences of '4-19-2' to prevent them from receiving additional pollen. Pollen from the early-maturing, rose-scented 'Xiangfei' grape, used as the male parent, is collected and applied to the flowering inflorescences of '4-19-2'. After application, the inflorescences are re-bagged and the branches are tied to the culture rack. The hybrid inflorescences are marked and covered with bird-proof bags. Seeds are harvested after the fruits mature.

[0114] 2020: Continue using the '4-19-2' mother plant and its adjacent '4-19-2' grafted tree as the female parent, bagging before flowering. Collect pollen from the male parent, '16-3-2' (the primary superior line selected in Example 1). Apply '16-3-2' pollen to the stigma of the '4-19-2' plant at peak flowering, re-bag, and complete the hybridization. Harvest the hybrids after fruit ripening.

[0115] Example 3

[0116] In 2020, the '4-19-2' and '16-3-2' grafted trees (or the intermediate parent original mother plants) were pre-cultured for flowering according to the method of the present invention. In 2021, the same number of '4-19-2' and '16-3-2' buds (born on one-year-old branches) were used as test materials, and the obtained scions were used to quickly produce inflorescences by the method of the present invention. At the same time, the obtained cuttings were rooted and propagated, and the flowering rates of the two methods were tracked and compared for 4 consecutive years. The flowering rate is calculated according to the theoretical value of bud flowering (i.e. the total number of buds for testing), and the flowering rate (%) = number of flowers blooming in the year / total number of buds for testing. The statistical results are shown in Table 1 below:

[0117]

[0118] In summary, the present invention has the following beneficial effects:

[0119] ① The entire breeding cycle of multi-generation hybrid breeding of grapes is shortened by about 4-5 years compared with conventional methods.

[0120] ②The bud utilization rate is twice that of the conventional two-bud cutting propagation method.

[0121] ③ Saves the land investment required for conventional clonal line propagation and field planting.

[0122] ④ Grafting adjacent large trees rationally reuses biological energy and reduces the difficulty of field management.

[0123] ⑤Optimize inflorescence development and increase seed yield.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements, or when the technical features in the above embodiments do not conflict with each other, can be combined in the manner described in the embodiments, and these modifications, replacements or combinations do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for shortening the grape breeding cycle by improving parent culture and grafting propagation, characterized in that: Here are the steps: S1. Pre-cultivation and selection of superior lines In the first year, the pre-selected superior hybrid seedlings were planted in the hybrid nursery and managed using a V-shaped frame with a single stem and single arm. When the new shoots grew to 30-40 cm in length, a strong new shoot was selected from each plant and set as the main stem. When the new shoots grew to 100-120 cm, the tops were pinched and the new shoots were tied 48-52 cm above the ground along the planting row to promote the germination and development of secondary shoots. The secondary shoots were pinched when they had 4 leaves. After the leaves fell in late autumn, the secondary shoots were pruned with two buds left. In the second year, when the plant has inflorescences, pinch off the new shoots when they have 5-7 leaves, and pinch off the secondary shoots with one leaf, and tie the new shoots horizontally or with the tips facing down to inhibit vegetative growth; after flowering, fertilize each plant to promote the initial differentiation of flower buds; after the fruit swells, fertilize each plant to promote the differentiation of flower organs; after the leaves fall in late autumn, prune back to keep two buds; In the third year, repeat the second year operation; S2. Screening of intermediate parents When the plant has inflorescence, relevant traits are scientifically evaluated to select offspring plants that meet breeding requirements and determine them as intermediate parents. After the individual plant used as the intermediate parent is determined, it is pruned after the leaves fall in late autumn, retaining two buds. The pruned branches are stored at low temperatures until the following spring for use in scion production. S3, rapid cloning of intermediate parents In the spring of the following year, after the grapes sprout, the refrigerated branches are taken out, the branches with buds are selected, and they are pruned into segments with single buds, which are then fully watered and used as scions. Select plants adjacent to the intermediate parent plant, cut them into rootstocks, make two incisions on the end face of each rootstock, insert a scion with a wedge-shaped end into each incision, seal the cut surface of the rootstock, the incision, and the wedge-shaped surface of the scion with grafting tape, exposing the bud of the scion, water the rootstock, and manage the original mother plant used as the intermediate parent in the same manner as usual; S4. Inflorescence development management After the scion sprouts, fertilize the rootstock to promote the growth of scion leaves. When the scion shoots grow to 20 cm, fertilize again to promote the growth of new shoots and the appearance of inflorescences. When treating the scion of a stock, keep the scion with inflorescence on the stock, and pinch off the 6-7 leaves above the flower, and keep the side shoots with 1 leaf and pinch them repeatedly; for the scion without inflorescence on the stock, pinch off the top of the 5th leaf, and keep only one side shoot near the top after the side shoots sprout; if both scions on the stock have no inflorescence, keep the scion with stronger growth potential, pinch off the top of the 5th leaf, and keep only one side shoot near the top after the side shoots sprout; Pinch off the 4-5 leaves on the nutrient branches without inflorescences on the original mother plant to promote the development of secondary shoots. After the secondary shoots grow to the appearance of inflorescences, pinch off the 4-5 leaves above the flowers and repeatedly remove the secondary shoots. One week before the flowering of the rootstock, scion and original mother plant, spray the leaves with fertilizers and growth regulators that promote the healthy development of floral organs to prepare for hybridization; S5. Harvesting hybrid seeds When the flower caps of single flowers on the inflorescence fall off, prepare for hybridization; bag the hybrid inflorescences and harvest the seeds after the fruits are ripe.

2. The method according to claim 1, characterized in that In S1, In the first year, the initially selected superior hybrid seedlings were planted in the hybrid nursery with a plant spacing of 0.7±0.1m×1.5±0.2m, and managed with a single stem and single arm of a V-shaped frame; after the main stem was determined, a water-soluble compound fertilizer with N:P:K=3:1:1 was applied to promote rapid growth of the plants; the new shoots were topped when they grew to 100-120cm to promote the germination of lateral shoots, and the new shoots were pulled and tied from 50cm above the ground along the planting row direction to promote the germination and development of lateral shoots; the lateral shoots were topped when they grew to 4 leaves; after the leaves fell in late autumn, the lateral shoots were pruned to leave two buds.

3. The method according to claim 1, characterized in that In S1, In the second year, when the plant has inflorescences, pinch off the new shoots when they grow to 5-7 leaves, pinch off the side shoots while leaving one leaf, and tie the new shoots horizontally or with the tips facing down to inhibit vegetative growth; after flowering, apply water-soluble fertilizer with N:P:K=1:2:3 to the roots of each plant, and spray 0.2% boric acid + 0.1% zinc sulfate on the leaves to promote the initial differentiation of flower buds; after the fruit swells, apply water-soluble fertilizer with N:P:K=1:2:3 to the roots of each plant, and spray 0.3% boric acid on the leaves to promote the differentiation of floral organs; after the leaves fall in late autumn, prune back to keep two buds.

4. The method according to claim 1, wherein In S2, when screening the intermediate parent plants, the relevant traits include but are not limited to one or a combination of fruit size, fruit uniformity, skin-residue ratio, fruit powder thickness, skin color, peeling difficulty, seed coat hardness, flesh crispness, acidity, soluble solids content, allergen content, aromatic substance types, fragrance, number of single seeds, phenological period parameters, secondary fruiting rate, fruit cracking rate after rain, sunburn sensitivity, chilling sensitivity, disease infectivity, storage and transportation resistance, new shoot internode length, and flower bud differentiation stability; when screening the intermediate parent plants, inflorescences or fruits usually appear in the third year to facilitate scientific evaluation of the relevant traits; if no inflorescences or fruits appear in the third year, the evaluation is delayed for one year; if certain traits need to be observed for many consecutive years, the cultivation and management measures of the second or third year of step S1 are repeated the following year, and observation and screening are carried out until the target plants are screened out.

5. The method according to claim 1, characterized in that In S3, after the grapes sprout in the spring of the following year, the following operations are performed in sequence: S31, taking out the refrigerated branches, selecting the branches with buds at the base, cutting the branches into segments with single buds, soaking them in sterile water to fully absorb water, and obtaining scions; S32, selecting a plant adjacent to the middle parent plant, cutting its trunk horizontally 35-45 cm above the ground to form a rootstock; S33: Make two vertical cuts 5-8 mm wide and 4-5 cm deep on the end of the stock. S34, with the scion eye as the front, make oblique cuts on the left and right sides of the scion to form wedge-shaped surfaces, with the length of the wedge-shaped surface matching the incision depth; S35, inserting the wedge-shaped surface of the scion into the incision of the stock, inserting a scion into each of the two incisions of one stock, and sealing the incision of the stock, the end surface of the stock, and the wedge-shaped surface of the scion with grafting tape, leaving only the bud of the scion exposed; S36. Water the roots of the rootstock to keep the soil moist; manage the original mother plant used as the intermediate parent as usual.

6. The method according to claim 5, characterized in that The operation method of S31 is as follows: take out the cold-stored branches, select the branches with buds at the base, cut the branches into segments with single buds, leave 1.4-1.6 cm above the buds and 5-8 cm below, soak them in distilled water for 12 hours to fully absorb water, and obtain scions; The operation method of S32 is as follows: select the adjacent plant to the middle parent plant, cut off the main trunk horizontally 40 cm above the ground to form the rootstock; The operation method of S33 is as follows: remove the bark below the end of the rootstock, and make two vertical cuts 5-8mm wide and 4-5cm deep on the end of the rootstock; The operation method of S34 is: with the bud of the scion as the front, make bevel cuts on both sides of the scion to form wedge-shaped surfaces. The length of the wedge surface matches the incision depth, which is 4-5cm. Make sure the wedge surface is smooth to facilitate effective healing of the grafting site. The operation method of S35 is: insert the wedge-shaped surface of the scion into the cut of the rootstock, keep at least one side of the cambium of the rootstock and the scion aligned, and seal the rootstock cut, the end face of the rootstock and the wedge-shaped surface of the scion with grafting tape, leaving only the bud of the scion exposed.

7. The method according to claim 1, characterized in that In S4, after scion budding, water-soluble fertilizer with N:P:K = 3:1:1 was applied to the rootstock root to promote scion leaf growth. When the scion shoot grew to 20 cm, water-soluble fertilizer with N:P:K = 1:1:1 was applied to the rootstock root to promote shoot growth and inflorescence appearance. If the secondary shoots grow and inflorescences appear, pinch off the top 4-5 leaves above the flowers and repeatedly remove the secondary shoots; One week before the flowering of the rootstock, scion and original mother plant, spray 0.2% boric acid + 0.1% zinc sulfate + 100 mg / L brassinolide on the leaves to promote the healthy development of floral organs and prepare for hybridization.

8. The method according to claim 1, characterized in that In S5, hybridization began when the flower cap of a single flower on the inflorescence fell off; If the middle parent is used as the male parent, the male parent inflorescence is collected for pollen collection and smeared on the female parent inflorescence with the stamens removed; if the middle parent is used as the female parent, the female parent inflorescence is artificially emasculated, the spike is bagged, and after the stigma secretes mucus, the male parent pollen is smeared on the stigma; After hybridization, the hybrid inflorescences are marked with bags and covered with bird-proof bags. After the fruits are ripe, the seeds are harvested.

Images