Method for hybridizing marigold

Abstract

The invention relates to the technical field of plant cultivation, and particularly discloses a marigold hybridization method. According to the marigold hybridization method, a female parent is treated when the outermost ligulate flower on a flower bud of the female parent grows to exceed calyx by 0.5-1 cm, and the method comprises the following steps: (1) performing flush pruning along the top end of the calyx, and removing ligulate flower petals exceeding the calyx; (2) cutting the bottommost part of the flower bud, and removing a part of the flower bud to form a notch capable of exposing small flowers in the remaining flower bud; the sequence of the step (1) and the step (2) is not limited; (3) cleaning all florets carrying stamens in the remaining flower buds from the notches; if the female parent only comprises the tongue-shaped flower, the floret refers to the tongue-shaped flower; if the female parent comprises a tongue-shaped flower and a tubular flower, the florets refer to the tongue-shaped flower and the tubular flower. The method disclosed by the invention is simple to operate, time-saving, labor-saving and low in cost, does not depend on a male sterile dual-purpose line, and can be used for rapidly obtaining hybrids among marigold germplasm resources.

Description

Technical Field

[0001] The invention relates to the technical field of plant breeding, in particular to a method for hybridizing marigolds. Background Art

[0002] marigold( Tagetes erecta L .) is an annual herbaceous plant of the genus Tagetes in the Asteraceae family, native to Mexico. Marigold flowers are rich in natural pigments, such as lutein, zeaxanthin, quercetin, etc. These pigments can be used as raw materials for food, feed, and medicine; α-terthiophene in marigold roots is an effective soil insecticide. At the same time, marigold flowers and leaves can be used as medicine, which has the effects of clearing heat and fire, resolving phlegm, replenishing blood, promoting menstruation, removing blood stasis and promoting new blood. Therefore, marigold plays an important role in the fields of chemical industry, food, environmental protection, and medicine.

[0003] At present, marigold seed production mainly relies on male sterile dual-purpose lines, and there is no report on artificial pollination between fertile flowers. Marigold flowers are capitula, with a large number of florets, divided into ligulate flowers and tubular flowers. Artificial emasculation is difficult and not conducive to hybridization. Therefore, it is necessary to further study the hybridization method of marigold. Summary of the invention

[0004] One of the purposes of the present invention is to provide a new method for hybridizing marigold which does not rely on male sterile dual-purpose lines to produce hybrids.

[0005] The present invention provides a method for hybridizing marigolds, wherein the female parent is processed when the outermost ligulate flowers on the flower buds of the female parent grow to be 0.5-1 cm larger than the calyx, and then used for hybridization with the male parent; The processing of the parent includes: (1) Trim flush along the top of the calyx and remove the ligulate petals that extend beyond the calyx; (2) Cut at the bottom of the flower bud to remove a portion of the flower bud, creating a gap that exposes the florets in the remaining flower bud; The order of steps (1) and (2) is not limited; (3) clearing all florets with stamens from the remaining flower buds from the notch; If the mother parent only includes ligulate flowers, the florets refer to ligulate flowers; if the mother parent includes ligulate flowers and tubular flowers, the florets refer to ligulate flowers and tubular flowers.

[0006] The present invention utilizes the characteristics of the outermost ligulate flowers of marigold flowers to develop a new method for producing hybrids that does not rely on male sterility dual-purpose lines. Specifically, marigold is a capitula, and each marigold flower contains multiple florets. Depending on the variety of marigold, the florets in some marigolds are all ligulate flowers, and the florets in some marigolds include both ligulate flowers and tubular flowers. Tubular flowers are a complete flower, including stamens, pistils, etc., and have the ability to self-pollinate and produce seeds. The present invention has found that in all varieties of marigolds, some ligulate flowers do not have stamens, which are natural sterile florets that can only be produced through the pollen of other florets, and such florets without stamens are generally located at the outermost part of the flower, and the characteristics of marigold flowering are that the outer florets develop quickly and the inner florets develop slowly. Based on this, the present invention has developed a new method for hybridizing marigolds by artificial pollination between fertile flowers by performing specific shearing treatment on the maternal buds at a specific developmental period.

[0007] The artificial pollination method between fertile flowers of the present invention gets rid of the restriction of male sterile dual-purpose lines, can create hybrids of any two marigold varieties, maximizes the use of hybrid advantages between marigold germplasm resources, and has low cost, simple operation, short cycle, and is conducive to popularization and application.

[0008] During the development of the present invention, an attempt was made to retain only one stamen-free flower in the center of each marigold flower as the mother parent, but experiments found that the remaining floret in this way was easy to dry up and fall off, and could not be effectively used as the mother parent. Therefore, after repeated research, the present invention of using the peripheral stamen-free ligulate flowers as the mother parent was finally obtained.

[0009] In the method of the present invention, the timing of processing the female parent is very critical, and the female parent needs to be processed when the outermost ligulate flowers on the female parent flower buds grow to exceed the calyx by 0.5-1 cm. If the processing timing is too early, the flower buds are too small, the internal florets are too small, and subsequent removal is difficult; if the processing timing is too late, the flower buds are too large, and the petals of the peripheral florets are too long, and the stigma is easily cut off when the exposed petals are removed, and the female parent available for pollination cannot be obtained. For this reason, the present invention sets a reasonable processing timing according to the development characteristics of each variety of marigold.

[0010] In step (1) of the method of the present invention, when trimming flush, avoid the column head.

[0011] In step (2) of the method of the present invention, the bottom of the flower bud is sheared along a direction perpendicular to the longitudinal axis of the flower bud.

[0012] The present invention shears the flower buds, thereby removing some of the florets carrying stamens and saving subsequent operation time, and providing an operation gap and space for removing the florets carrying stamens in the remaining flower buds, so that subsequent operations can be carried out smoothly while not easily damaging the peripheral target florets (the ligulate flowers without stamens).

[0013] In step (2) of the method of the present invention, the removed flower buds account for 1 / 3 to 1 / 2 of the entire flower buds.

[0014] The size of the flower buds to be removed in the present invention is not limited, as long as it can facilitate the successful removal of the florets carrying stamens.

[0015] In the method of the present invention, the mother parent is bagged after being treated for later use.

[0016] In the method of the present invention, pollination is carried out after the stigmas of the remaining florets after the treatment of the female parent emerge from the petals.

[0017] Generally, 1-2 days after the treatment of the female parent, the stigma of the remaining florets (ray-shaped flowers) will have petals, which can be used for subsequent cross-pollination. The seeds can be harvested 15-20 days after pollination.

[0018] In the method of the present invention, when hybridizing with the male parent, pollen of the healthy and strong male parent is collected and applied to the stigma of the remaining florets after the female parent is treated.

[0019] In the method of the present invention, when applying pollen, the florets remaining after the treatment of the female parent are temporarily fixed (eg, held by hand) to prevent the florets from falling during pollination.

[0020] In the method of the present invention, the pollination times are 1-3 times, preferably 2 times.

[0021] In the method of the present invention, each pollination interval is 24 hours.

[0022] The beneficial effects of the present invention are at least: (1) The present invention breaks away from the constraints of male sterile dual-purpose lines and can create hybrids of any two marigold varieties, thereby maximizing the use of hybrid advantages between marigold germplasm resources; (2) The method of the present invention has the advantages of low cost, simple operation and short cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 These are photos of marigold hybridization before and after treatment. The left picture shows the marigold mother plant to be treated, and the right picture shows the mother plant after treatment.

[0024] Figure 2 The left picture shows the mother plant that continues to grow after treatment; the middle picture shows the mother plant that has stigma and petals after treatment, and the right picture shows the control mother plant that has not been pollinated after treatment.

[0025] Figure 3 Photos of ray flowers (left) and tubular flowers (right). DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention will be described in detail below in conjunction with examples. It should be understood that the following examples are provided only for the purpose of illustration and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0027] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are commercially available or prepared according to conventional methods in the art unless otherwise specified.

[0028] The specific information of the marigold material used in the examples of the present invention is shown in Table 1.

[0029] Table 1

[0030] Scarlet No. 1 refers to the record in Chen Liwen, Tang Nan. Evaluation of the main agronomic traits of different varieties of pigmented marigolds[J]. Journal of Anhui Agricultural Sciences, 2021, 49(4): 53-55.

[0031] Guanying can be purchased from Chifeng Zhongguan Seed Co., Ltd. Mountain Range can be purchased from Jiuquan Jinqiu Horticultural Seedling Co., Ltd.

[0032] Example 1

[0033] This embodiment provides a method for hybridization of marigolds, which is as follows: 1. Test materials

[0034] Scarlet One is the male parent and Crown Winning is the female parent.

[0035] 2. When the outermost ligulate flowers on the mother plant's buds grow to 1 cm above the calyx (see Figure 1 The left picture in the figure) is used for maternal processing, as follows: (1) Trim flush with the top of the calyx (be careful not to cut off the stigma), remove the ligulate petals that extend beyond the calyx, avoid the petals blocking the stigma during pollination, and increase the seed setting rate.

[0036] (2) Cut a notch in the flower bud from the bottom.

[0037] Specifically, in this embodiment, flush shearing is performed at the bottom of the flower bud along a direction perpendicular to the longitudinal axis of the flower bud, removing half of the flower bud and forming a gap that can expose the florets in the remaining flower bud.

[0038] (3) Remove all the florets with stamens from the remaining buds through the gaps formed above.

[0039] Specifically, clean the florets inside along the gap, and observe whether the florets have pollen sacs during cleaning. If so, clean them up until only the tongue-shaped florets without pollen sacs on the periphery of the buds remain. Figure 1 Right picture in .

[0040] (4) After trimming, put the fruits into a bag (parchment bag) and set aside.

[0041] 3. Collect pollen from the male parent and then pollinate

[0042] Wait until the stigma of the mother plant flower (only the ligulate flowers without stamens remain) has petals (see Figure 2 Select healthy and strong male plants as spare plants for collecting pollen, use a brush to gently dip the pollen in the male flowers, and then transfer the pollen to the treated female flowers. When pollinating, fix the female florets (the remaining stamen-free ligulate flowers after the above treatment) by hand, and gently apply the pollen on the brush to the stigma to prevent the florets from falling. Finally, continue bagging (parchment bag) and record the pollination time and pollination variety information. Perform artificial pollination twice in the same way, once a day.

[0043] 4. Seed harvesting

[0044] Seven days after pollination, the seeds of the successfully pollinated flowers can be observed to turn black and hard (see Figure 2 Seeds can be harvested 15-20 days after pollination.

[0045] The treated but unpollinated control female plants produced no seeds (see Figure 2 (right image).

[0046] 5. Results and statistics

[0047] 120 seeds were randomly selected from the harvested seeds for planting experiments. No sterile plants appeared in the final offspring, indicating that the seeds obtained were hybrids, not produced by self-pollination of the female parent.

[0048] The formula for calculating the hybrid seed setting rate is: hybrid seed setting rate (%) = (number of hybrids / number of female florets used for hybridization) × 100%.

[0049] In this experiment, a total of 900 female florets were pollinated, and finally 416 hybrid seeds were harvested, with a hybrid seed setting rate of 46.22%.

[0050] Example 2

[0051] This example provides a method for hybridization of marigolds, which is basically the same as the method in Example 1, except that Scarlet One is used as the male parent and Mountain Range is used as the female parent (photos of some of its ligulate flowers and tubular flowers are shown in Figure 3). The main stem color of Scarlet No. 1 is purple, and the main stem color of Mountain is green. Purple is dominant over green. When the outermost ligulate flowers on the mother parent buds grow to 0.5 cm longer than the calyx, the mother parent treatment is carried out. The order of steps (1) and (2) of the mother parent treatment is interchanged.

[0052] Results In this experiment, a total of 82 female florets were pollinated, and finally 30 hybrids were harvested, with a hybrid seed setting rate of 36.59%. The 30 hybrids were sown and the color of their main stems was observed. The main stems of the 30 hybrids were purple, indicating that the purity of the hybrids obtained after hybridization using the method of the present invention was 100%.

[0053] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for hybridizing marigold, characterized in that: When the outermost ligulate flowers on the female parent's flower buds grow to 0.5-1 cm above the calyx, the female parent is processed and then used for hybridization with the male parent; The processing of the parent includes: (1) Trim flush along the top of the calyx and remove the ligulate petals that extend beyond the calyx; (2) Cut at the bottom of the flower bud to remove a portion of the flower bud, creating a gap that exposes the florets in the remaining flower bud; The order of steps (1) and (2) is not limited; (3) clearing all florets with stamens from the remaining flower buds from the notch; If the mother parent only includes ligulate flowers, the florets refer to ligulate flowers; if the mother parent includes ligulate flowers and tubular flowers, the florets refer to ligulate flowers and tubular flowers.

2. The method according to claim 1, characterized in that In step (1), avoid the column heads when trimming flush.

3. The method according to claim 1 or 2, characterized in that: In step (2), the bottom of the flower bud is cut along a direction perpendicular to the longitudinal axis of the flower bud.

4. The method according to any one of claims 1 to 3, characterized in that: In step (2), the removed flower buds account for 1 / 3 to 1 / 2 of the entire flower buds.

5. The method according to any one of claims 1 to 4, characterized in that: The female parent is bagged after being processed for later use.

6. The method according to any one of claims 1 to 5, characterized in that: After the stigma of the remaining florets after the treatment of the female parent emerges from the petals, pollination is performed.

7. The method according to any one of claims 1 to 6, characterized in that: When hybridizing with the male parent, pollen from the healthy and vigorous male parent is collected and applied to the stigma of the remaining florets after the treatment of the female parent.

8. The method according to claim 7, characterized in that When applying pollen, the remaining florets after the female parent treatment are temporarily fixed to prevent the florets from falling during pollination.

9. The method according to any one of claims 6 to 8, characterized in that: The pollination frequency is 1-3 times, preferably 2 times.

10. The method according to claim 9, characterized in that Each pollination interval is 24 hours.

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