Method for promoting reverse recovery of flower type of highly double peony variety

Abstract

This invention discloses a method for inducing the reversal of flower shape and restoring fertility in highly double-flowered peony varieties. The method involves artificially intervening in the flower buds of highly double-flowered peony varieties to reverse the flower shape, resulting in the formation of normal stamen and pistil tissues. The anthers and stigmas develop normally or partially normally, thus restoring the fertility of the highly double-flowered peony varieties. The restoration of fertility in highly double-flowered peony varieties is beneficial for cultivating peony varieties with more petals and more complex flower shapes. As the number of petal layers increases, the flowering period tends to be later, providing more material selections for the cultivation of new late-flowering peony varieties. It also offers a good solution to the current shortage of late-flowering peony varieties and the enrichment of late-flowering parent materials. By cultivating more new late-flowering peony varieties and extending the overall flowering period of peonies, greater social and economic benefits will be achieved.

Description

Technical Field

[0001] This invention relates to the field of peony breeding technology, and in particular to a method for inducing the reversal of flower shape and restoration of fertility in highly double-petaled peony varieties. Background Technology

[0002] Peony, a perennial deciduous shrub belonging to the genus Paeonia in the family Paeoniaceae, is a very important traditional ornamental flower and medicinal plant in China. It has also recently emerged as an excellent woody oil crop. Native to China, the peony possesses high ornamental and cultural value, and has been revered as the "King of Flowers" since the Tang Dynasty. Its main cultivation areas cover North China, Northwest my country, Central China, East China, and parts of Southwest China, with successful cultivation also achieved in some high-altitude areas of South China in recent years. Over its 1600-year cultivation history in my country, through natural evolution, artificial domestication, and hybridization, over 1300 ornamental varieties have been developed today.

[0003] Highly double-petaled peony varieties, which are very popular among the public, often have severely degenerated reproductive organs. They usually have large flower heads, and the stamens and pistils are petalized to varying degrees, or even completely petalized, and cannot develop into normal anthers and stigmas, thus losing their fertility. However, these varieties have very good genetic diversity. How to use these genetic resources to cultivate peony varieties with more advanced and complex flower shapes has become a difficult problem for peony breeders.

[0004] During the development of peony flower buds, the transformation from stamen and pistil primordia to petal primordia is a result of the continuous differentiation of the marginal meristem of the vascular bundles and the continuous increase in the number of vascular bundles. The inventors observed during breeding that in highly double-flowered peony varieties, when the dominant flower buds at the branch tips are damaged, some flower buds located at the lower part of the branch, which are usually at a disadvantage and cannot grow normally, gain the opportunity to develop (normally these flower buds do not germinate due to apical dominance). However, due to positional effects and nutritional limitations, the development of these flower buds is significantly affected, lagging behind the differentiation of the flower buds at the top. Furthermore, the formation of petals is significantly hindered; not all stamen and pistil primordia can transform into petal primordia, failing to form normal stamen and pistil tissue, and thus failing to develop normal anthers and stigmas, losing their fertility. This affects the fertility of highly double-flowered peony varieties and is not conducive to cultivating peony varieties with more petals and more complex flower shapes. As the number of petal layers increases, the flowering period tends to be later, resulting in a shortage of late-flowering peony varieties and a lack of late-flowering parent materials, thus limiting the selection of materials for cultivating new late-flowering peony varieties. Summary of the Invention

[0005] To solve the above-mentioned technical problems, this invention provides a method for inducing the reversal of flower shape and restoration of fertility in highly double-flowered peony varieties. Through artificial intervention, the method induces the reversal of flower shape in highly double-flowered peony varieties, especially the restoration of fertility in varieties with completely petaloid pistils and stamens, forming normal pistil and stamen tissues, and restoring the development of anthers and stigmas to normal or partially normal, thereby realizing the fertility of highly double-flowered peony varieties.

[0006] The technical solution adopted in this invention is: a method for inducing the reversal of flower shape and restoration of fertility in highly double-petaled peony varieties, comprising the following steps:

[0007] Step 1: In spring, after the peony enters the budding stage, prune 1-2 flower buds at the top of the strong branches, leaving only 1 flower bud at the bottom of the branch. This removes the apical dominance and stimulates the development of the weaker flower buds at the bottom.

[0008] Step 2: Every morning at 9:00 AM, apply 300-320 ppm gibberellin GA3 to the bud scales of the retained flower buds once, until the retained flower buds enter the budding stage;

[0009] Step 3: After the flower buds and tender leaves emerge from the scales, promptly remove the bottom 2-3 leaves from the flower branch to promote flower bud development.

[0010] Step 4: After the flower buds emerge from the bud scales and enter the bud-forming stage, apply 150-160 ppm gibberellin GA3 daily to the base of the flower buds. Continue this process until the flower buds develop into large bell-shaped buds, at which point the use of gibberellin should be discontinued.

[0011] Step 5: During the growing season, strengthen the water and fertilizer management of peony plants to ensure that the plants meet their needs for water and nutrients for rapid growth.

[0012] Step 6: After the flower buds enter the color-revealing stage and the petals loosen, remove all the petals before they open. Collect the stamens with tweezers, mark and store them. While protecting the pistil, remove all the stamens and seal the flower head with a breeding bag. Artificial pollination will be carried out when the stigma matures.

[0013] Step 7: Bring the collected anthers indoors, spread them out on clean tracing paper, separate them by variety to dry, and collect the released mature pollen for hybridization pollination. The room temperature should be controlled between 16℃ and 22℃.

[0014] Step 8: On the 2nd to 3rd day after the stigma begins to secrete mucus, open the breeding bag at 9 to 10 am for artificial pollination. Quickly apply the male parent pollen to the stigma, seal the flower head in time, mark the groups, and repeat the pollination once on the 2nd day.

[0015] In step two, applying gibberellin GA3 to the bud scales of flower buds, and in step four, applying gibberellin GA3 to the base of flower buds, can accelerate cell elongation, promote stem and leaf growth, and flower bud differentiation. The application site affects petal development, and different concentrations have a crucial impact on peony flower bud development. Gibberellin GA3, as a growth-promoting hormone, has the strongest physiological activity and plays a multifaceted role in promoting the growth and development of cultivated peonies. Applying gibberellin solution to buds breaks dormancy and initiates growth; after growth begins, applying gibberellin to young buds can rapidly promote flower bud growth. Increasing the number of GA3 hormone treatments ensures a continuous stimulating effect of GA3 on flower buds and buds, which is beneficial for the accumulation of metabolites and activation of the cambium.

[0016] Step six involves artificial pollination. Peonies are cross-pollinated plants, but they have a certain success rate in self-pollination. Complete removal of the petals can effectively promote the normal development of their reproductive organs and the smooth completion of the fertilization process.

[0017] In step seven, the room temperature is controlled between 16℃ and 22℃. Too low a temperature will slow down the pollen maturation, while too high a temperature will cause the pollen to die.

[0018] In step eight, pollination occurs on the 2nd to 3rd day after the stigma begins to secrete mucus. The timing of pollination affects the affinity between pollen and stigma. Studies have shown that delayed pollination can effectively improve the success rate of hybridization and fertilization after flower shape reversal in highly double-flowered peony varieties.

[0019] Step eight, pollination, takes place between 9 and 10 a.m. The breeding bag is opened for artificial pollination, and the flower head is sealed immediately afterward. This time period is the optimal time for pollination in peony hybridization breeding, as it is the peak time of day for stigma secretion of mucus. Selected pollen is easily stimulated by the mucus to germinate and form pollen tubes, which then enter the ovary to complete the fertilization process. Sealing the flower head promptly after pollination prevents infection of the wound and cross-pollination by external pollen.

[0020] The beneficial effects of this invention are as follows: This invention involves artificial intervention in highly double-flowered peony varieties from the flower bud stage, causing a reversal in flower shape and the formation of normal pistil and stamen tissues. The development of anthers and stigmas is restored to normal or partially normal, thereby achieving the fertility of highly double-flowered peony varieties. The restoration of fertility in highly double-flowered peony varieties is beneficial for cultivating peony varieties with more petals and more complex flower shapes. Furthermore, as the number of petal layers increases, the flowering period tends to be later, providing more material choices for the cultivation of new late-flowering peony varieties. This also provides a good solution to the current shortage of late-flowering peony varieties and the enrichment of late-flowering parent materials. By cultivating more new late-flowering peony varieties and extending the overall flowering period of peonies, greater social and economic benefits will be achieved. Attached Figure Description

[0021] Figure 1 The two buds retained after pruning the 'Coral Terrace' peony in Example 1;

[0022] Figure 2 Example 1: 'Coral Platform' terminal bud flower (crown type);

[0023] Figure 3 Image of two-bud flowers (rose type) after pruning of 'Coral Terrace' in Example 1;

[0024] Figure 4 Seeds of the hybrid of 'Coral Platform' (♀) × 'Neon Color' (♂) from Example 1;

[0025] Figure 5 The two buds retained after pruning the 'Neon Fantasy' peony in Example 2;

[0026] Figure 6 Example 2 'Neon Colors' Top Bud Flower (Pavilion Type);

[0027] Figure 7 Image of the two-bud flower (chrysanthemum type) after trimming in Example 2, 'Neon Colors';

[0028] Figure 8 Seeds of the hybrid of 'Neon Color' (♀) × 'Coral Platform' (♂) in Example 2. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The method of this invention can be used to reverse the flower shape of highly double-flowered peony varieties and restore their fertility, enabling artificial hybridization breeding of peonies. The specific implementation of this invention will be further described in detail below with reference to examples.

[0031] Example 1

[0032] A method for inducing the reversal of flower shape and restoration of fertility in highly double-flowered peony varieties involves hybridization using 'Coral Terrace' (crown type) as the female parent and 'Neon Splendor' as the male parent; the method includes the following steps:

[0033] Step 1: In spring, after the 'Coral Terrace' (crown type) enters the budding period, prune 1-2 flower buds at the top of the strong branches, leaving only 1 flower bud at the bottom of the branch, removing the terminal bud dominance and stimulating the development of the weaker flower buds at the bottom.

[0034] Step 2: Every morning at 9:00 AM, apply 300 ppm gibberellin (GA3) to the bud scales of the retained flower buds once, until the retained flower buds enter the budding stage;

[0035] Step 3: After the flower buds and tender leaves emerge from the scales, promptly remove the bottom 2-3 leaves from the flower branch to promote flower bud development.

[0036] Step 4: After the flower buds emerge from the bud scales and enter the bud stage, apply 150 ppm gibberellin (GA3) daily to the base of the flower buds. Continue this treatment until the flower buds develop into large bell-shaped buds, at which point stop using gibberellin.

[0037] Step 5: During the growing season, strengthen the water and fertilizer management of peony plants to ensure that the plants meet their needs for water and nutrients for rapid growth.

[0038] Step 6: After the flower buds enter the color-revealing stage and the petals loosen, remove all the petals before they open. Collect the stamens with tweezers, mark and store them. While protecting the pistil, remove all the stamens and seal the flower head with a breeding bag. Artificial pollination will be carried out when the stigma matures.

[0039] Step 7: Bring the collected anthers indoors, spread them out on clean tracing paper, separate them by variety to dry, and collect the released mature pollen for hybridization pollination. The room temperature should be controlled at 16℃~20℃.

[0040] Step 8: On the 2nd to 3rd day after the stigma begins to secrete mucus, open the breeding bag at 9 to 10 am for artificial pollination. Quickly apply the male parent pollen 'Neon Splendor' to the stigma, seal the flower head in time, mark the groups, and repeat the pollination once on the 2nd day.

[0041] Example 2

[0042] A method for inducing the reversal of flower shape and restoration of fertility in highly double-flowered peony varieties involves hybridization using 'Neon Splendor' (pavilion type) as the female parent and 'Coral Terrace' as the male parent; the method includes the following steps:

[0043] Step 1: In spring, after the 'Neon Splendor' (pavilion type) enters the budding period, prune 1-2 flower buds at the top of the strong branches, leaving only 1 flower bud at the bottom of the branch, removing the terminal bud dominance and stimulating the development of the weaker flower buds at the bottom.

[0044] Step 2: Every morning at 9:00 AM, apply 320ppm gibberellin (GA3) to the bud scales of the retained flower buds once, until the retained flower buds enter the budding stage;

[0045] Step 3: After the flower buds and tender leaves emerge from the scales, promptly remove the bottom 2-3 leaves from the flower branch to promote flower bud development.

[0046] Step 4: After the flower buds emerge from the bud scales and enter the bud-forming stage, apply 160ppm gibberellin (GA3) daily to the base of the flower buds. Continue this process until the flower buds develop into large bell-shaped buds, at which point the use of gibberellin should be discontinued.

[0047] Step 5: During the growing season, strengthen the water and fertilizer management of peony plants to ensure that the plants meet their needs for water and nutrients for rapid growth.

[0048] Step 6: After the flower buds enter the color-revealing stage and the petals loosen, remove all the petals before they open. Collect the stamens with tweezers, mark and store them. While protecting the pistil, remove all the stamens and seal the flower head with a breeding bag. Artificial pollination will be carried out when the stigma matures.

[0049] Step 7: Bring the collected anthers indoors, spread them out on clean tracing paper, separate them by variety and let them air dry. Collect the released mature pollen for hybridization pollination. The room temperature should be controlled at 20℃~22℃.

[0050] Step 8: On the 2nd to 3rd day after the stigma begins to secrete mucus, open the breeding bag at 9 to 10 am for artificial pollination. Quickly apply the male parent pollen 'Coral Terrace' to the stigma, seal the flower head in time, mark the groups, and repeat the pollination once on the 2nd day.

[0051] like Figure 1-8 As shown, the method of this invention can induce the reversal of flower shape and restoration of fertility in highly double-flowered peony varieties. In Example 1, artificial hybridization breeding of peony was carried out between 'Coral Terrace' (♀) and 'Neon Radiance' (♂). In Example 2, artificial hybridization breeding of peony was carried out between 'Neon Radiance' (♀) and 'Coral Terrace' (♂). In both cases, the method of this invention was used to artificially intervene from the flower bud stage, causing the flower shape to reverse, forming normal pistil and stamen tissue, and restoring the development of anthers and stigmas to normal or partially normal. The hybrid seeds produced good fruit, thereby realizing the fertility of highly double-flowered peony varieties, especially the fertility of varieties with completely petalized pistils and stamens. The restoration of fertility in highly double-flowered peony varieties is beneficial for cultivating peony varieties with more petals and more complex flower shapes. As the number of petal layers continues to increase, the flowering period tends to be later, which provides more material selection for the breeding of new late-flowering peony varieties and also provides a good solution to the current shortage of late-flowering peony varieties and the enrichment of late-flowering parent materials.

Claims

1. A method for restoring fertility to a highly double peony variety by reversing the flower type, characterized in that, Includes the following steps: Step 1: In spring, after the peony enters the budding stage, prune 1-2 flower buds at the top of the strong branches, leaving only 1 flower bud at the bottom of the branch. This removes the apical dominance and stimulates the development of the weaker flower buds at the bottom. Step 2: Every morning at 9:00 AM, apply 300-320 ppm gibberellin GA3 to the bud scales of the retained flower buds once until the retained flower buds enter the budding stage. Step 3: After the flower buds and tender leaves emerge from the scales, promptly remove the bottom 2-3 leaves from the flower branch to promote flower bud development. Step 4: After the flower buds emerge from the bud scales and enter the bud stage, apply 150-160 ppm of gibberellin GA3 daily to the base of the flower buds. Continue this treatment until the flower buds develop into large bell-shaped buds, at which point the use of gibberellin should be discontinued. Step 5: During the growing season, strengthen the water and fertilizer management of peony plants to ensure that the plants meet their needs for water and nutrients for rapid growth. Step 6: After the flower buds enter the color-revealing stage and the petals loosen, remove all the petals before they open. Collect the stamens with tweezers, mark and store them. While protecting the pistil, remove all the stamens and seal the flower head with a breeding bag. Artificial pollination will be carried out when the stigma matures. Step 7: Bring the collected anthers indoors, spread them out on clean tracing paper, separate them by variety to dry, and collect the released mature pollen for hybridization pollination; Step 8: On the 2nd to 3rd day after the stigma begins to secrete mucus, open the breeding bag at 9 to 10 am for artificial pollination. Quickly apply the male parent pollen to the stigma, seal the flower head in time, mark the groups, and repeat the pollination once on the 2nd day.

2. The method for promoting the recovery of fertility of the flower type of a highly double peony variety according to claim 1, characterized in that: In step seven, the room temperature should be controlled between 16℃ and 22℃.

Images