CN112586348B

CN112586348B - Watermelon tetraploid propagation method and application thereof

Info

Publication number: CN112586348B
Application number: CN202010965340.3A
Authority: CN
Inventors: 刘文革; 赵胜杰; 朱红菊; 路绪强; 何楠
Original assignee: Zhengzhou Fruit Research Institute CAAS
Current assignee: Zhengzhou Fruit Research Institute CAAS
Priority date: 2020-09-15
Filing date: 2020-09-15
Publication date: 2022-07-19
Anticipated expiration: 2040-09-15
Also published as: CN112586348A

Abstract

The invention discloses a watermelon tetraploid propagation method, which comprises using diploid watermelon homozygous inbred line as material, and using colchicine to perform tetraploid propagation in seedling stageCarrying out ploid induction; selecting a tetraploid watermelon plant which is successfully mutagenized as a material, taking the vine of the tetraploid watermelon plant as a scion and the strong west graft as a stock, grafting by using a grafting method, and performing grafting according to a management method of a grafted seedling until the grafted seedling survives; and (4) planting the surviving grafted seedlings, selfing and pollinating until the fruits are mature. The watermelon tetraploid propagation method provided by the invention is applied to seedless watermelon breeding. The invention realizes the artificial induction of tetraploid watermelon T₀The rapid increase of the number of generation plants, fruits and seeds accelerates the utilization of tetraploid watermelons and shortens the breeding process of triploid seedless watermelons.

Description

Watermelon tetraploid propagation method and application thereof

Technical Field

The invention belongs to the technical field of agricultural planting and cultivation, relates to a tetraploid watermelon propagation technology, and particularly relates to a method for accelerating utilization of newly mutagenized tetraploid watermelons through vine grafting.

Background

Watermelon is a garden crop widely planted in the world and is also one of the ten important fruits in the world. Triploid seedless watermelon is one of gardening crops with the largest planting area by utilizing the polyploid technology in the production at present, and compared with diploid watermelon, the triploid seedless watermelon has the advantages of strong stress resistance, high sugar content, seedless property, storage and transportation resistance, high yield and the like. In order to obtain an excellent triploid seedless watermelon variety, the tetraploid material obtained by doubling diploid watermelon chromosomes becomes the key of variety breeding, but the natural tetraploid watermelon plants, particularly the tetraploid watermelon plants with excellent agronomic characters, have fewer sources, so the artificially induced tetraploid watermelon plants are used as the main sources of the parents for the excellent triploid watermelon variety breeding.

Colchicine induction is one of the important ways to obtain tetraploid watermelons. The tetraploid watermelon current plant formed by colchicine-induced doubling is generally called T₀Instead, they are called "immature tetraploids" by scholars. Due to the action of colchicine, T₀The normal physiological process of the generation plants is affected specifically, and the following physiological status situations often appear: the plant only extends the vine and does not bloom; the plants are not easy to sit on the melons; the pregnancy is reduced, and the single melon has few or no seeds after sitting. Can not obtain T₀Substitute for plantThe seeds of the strain are important indexes for measuring the mutagenesis success rate of the tetraploid watermelon, therefore, the strain is used for measuring the T₀More tetraploid watermelon seeds are obtained during generation.

Grafting is to graft the branch or bud of one plant onto the stem or root of another plant, so that the two parts connected together can grow into a complete plant. At present, the grafting technology is generally applied to watermelon cultivation. In order to quickly obtain a new triploid seedless watermelon variety meeting the market demand, T is realized by a grafting technology₀The propagation of the generation plants is a practical agronomic measure.

Disclosure of Invention

The purpose of the invention is as follows: taking the tendrils of the new mutagenic tetraploid watermelon plants as scions, and increasing T by a grafting technology₀The number of the generation plants is large, and the rapid propagation of the tetraploid watermelons is realized.

In order to realize the aim, the invention provides a tetraploid watermelon propagation method, which realizes the artificial induction of T of tetraploid watermelons₀The rapid increase of the number of generation plants, fruits and seeds accelerates the utilization of tetraploid watermelons and shortens the breeding process of triploid seedless watermelons.

A method for propagating the tetraploid watermelon includes such steps as artificially inducing the diploid watermelon seedlings to become tetraploid plants, using the vine of tetraploid watermelon as scion and the strong scion as stock, and grafting.

Specifically, the watermelon tetraploid propagation method comprises the following operation steps:

using diploid watermelon homozygous inbred line as material, using colchicine (colchicine) to make tetraploid induction in seedling stage;

selecting a tetraploid watermelon plant which is successfully mutagenized as a material, taking the vine of the tetraploid watermelon plant as a scion and the strong west graft as a stock, grafting by using a grafting method, and performing grafting according to a management method of a grafted seedling until the grafted seedling survives;

and (4) planting the surviving grafted seedlings, selfing and pollinating until the fruits are mature.

As one of the preferred embodiments of the watermelon tetraploid propagation method, the operation of the splicing method is as follows: a blade is used for cutting off a rootstock cotyledon at an angle of 30 degrees upwards, a blade is used for cutting off a scion at an angle of 30 degrees upwards, the rootstock and the scion are attached, and then a grafting clip is used for clamping a wound. The reason for selecting the grafting method is that compared with the conventional watermelon grafting scion, the watermelon vine is thicker, the grafting method is convenient to operate, and the survival rate is high.

As one of the preferable embodiments of the watermelon tetraploid propagation method, the scion is selected from a vine with a growing point, a vine with one node, or a vine with a plurality of nodes. The invention uses 5 diploid homozygous inbred lines of Zhengzhou fruit tree institute of Chinese academy of agricultural sciences as breeding materials, and tests prove that the watermelon tetraploid plants can be obtained by adopting the grafting technology of the invention.

As one of the preferable embodiments of the watermelon tetraploid propagation method, the invention further provides a seedling management method after grafting. Specifically, after grafting is finished, covering the grafted seedlings with a plastic film, covering a sunshade net, and shading and moisturizing within 2d after grafting; 3d, starting to uncover the film to release air and give illumination, covering the film after the water drops on the grafted seedlings are dried, and releasing air once in the morning and at night; the time of air release and illumination is sequentially prolonged for the next week until the grafted seedling survives.

As one of the preferred embodiments of the watermelon tetraploid propagation method, the specific operation of inducing the tetraploid of the present invention is: manually breaking the shell of the diploid watermelon homozygous inbred line seed, soaking in warm water for 2h, accelerating germination for 24h at 32 ℃, and sowing; removing seedling apical centers after seedling cotyledons are unfolded, performing tetraploid induction by using colchicine dripping seedlings with mass concentration of 0.2%, dripping 1 drop in the morning and at night, and treating for 6 d.

In addition, the invention further provides application of the watermelon tetraploid propagation method in seedless watermelon breeding. The watermelon tetraploid propagation method can provide a parent material for seedless watermelon breeding.

Compared with the prior art, the watermelon tetraploid propagation method has the beneficial effects or advantages that: 1) the invention can effectively graft watermelon vineIncrease the mutagenesis contemporary (T) of tetraploid watermelon₀) The number of plants is increased, so that the purpose of propagation of tetraploid watermelons is achieved; 2) the method of the invention is adopted in the process of artificially inducing the tetraploid watermelons, so that the mutagenesis efficiency can be greatly improved, and the mutagenesis T can be increased₀The plant number, fruit number and seed number of the generation accelerate the utilization of the new mutagenic tetraploid watermelon and shorten the breeding process of the triploid seedless watermelon.

Drawings

FIG. 1 is a vine of tetraploid watermelons with growing points used in an embodiment of the present invention.

Fig. 2 is a vine of tetraploid watermelons with a node used in an embodiment of the present invention.

Fig. 3 is a vine of tetraploid watermelons with two nodes used in an embodiment of the present invention.

FIG. 4 is a graph of the survival of grafted vine seedlings of an example of the present invention, the scion used being the vine of a tetraploid watermelon with growing points.

Fig. 5 is a graph showing the survival of grafted vine shoots of tetraploid watermelons with one node according to an embodiment of the present invention.

FIG. 6 is a graph of the survival of grafted vine seedlings of an embodiment of the present invention, the scion used is a vine of a tetraploid watermelon with two nodes.

Detailed Description

The following describes the watermelon tetraploid propagation method and the application thereof in detail with reference to the examples.

(1) Mutagenic tetraploids

5 excellent diploid watermelon homozygous inbred lines are selected as materials, specifically Crimson sweet, XBM, Yu2, Yu10 and Charlston Gray (see Table 1 for details). Preparing 100 seeds for each part of material, manually breaking the shells of the seeds, soaking the seeds in warm water for 2 hours, accelerating germination at 32 ℃ for 24 hours, and sowing the seeds in a greenhouse. After the cotyledon of the seedling is unfolded, the apical center is removed, tetraploid induction is carried out by dripping 0.2 percent of colchicine for 1 time in the morning and at night, and the treatment lasts for 6 days. And (4) keeping the temperature and moisture at the seedling stage, planting the watermelon seedlings in a greenhouse after the watermelon seedlings grow out of the top centers again, and performing fine management.

The 5 parts of diploid homozygous inbred line material selected above is a breeding material of Zhengzhou fruit tree research institute of Chinese academy of agricultural sciences.

(2) Preliminary identification of tetraploids

And (4) preliminarily judging whether the tetraploid is successfully mutagenized according to the shape of the watermelon plant leaves and the thickness of the stems. Compared with diploid watermelons, tetraploid watermelon leaf characteristics: blunt leaf tip, widened transverse diameter, dark leaf color and uneven leaf surface. Tetraploid watermelon stem characteristics compared to diploid watermelons: thick stem, short internode and easy to break. The results of the initial identification of tetraploid mutagenesis are shown in table 1.

TABLE 1 preliminary identification results of tetraploid watermelons by mutagenesis

(3) Tetraploid vine grafting

Selecting tetraploid plants which are successfully mutagenized as materials, cutting tetraploid plant vines by using a blade as scions, taking western grafts as stocks, grafting by using a grafting method, managing according to a grafting method after grafting until the tetraploid plants survive, wherein the survival rate of the grafting seedlings is detailed in table 2.

The scions selected for this example are shown in FIGS. 1-3. Particularly the foremost vine with growing point (terminal bud), or the vine with one node or the vine with a plurality of nodes (at least 2 nodes). The survival diagrams of the grafted tendrils in the embodiment of the invention are shown in fig. 4-6.

TABLE 2 grafting survival rate of induced tetraploid watermelons

The grafting method comprises the following specific steps: and (3) cutting off a cotyledon of the stock by using a disinfection blade at an angle of 30 degrees upwards, cutting off the scion by using a blade at an angle of 30 degrees upwards, and clamping the wound by using a grafting clamp after the stock is attached to the scion.

The grafted seedling management method in this embodiment is as follows: immediately covering the grafted seedlings with a plastic film after grafting, covering a sunshade net, shading and moisturizing within 2d after grafting. And 3d, beginning to uncover the film to release air and give light, covering the film after the water drops on the grafted seedlings are dried, and releasing air once in the morning and at night. The time of air release and illumination is sequentially prolonged for the next week until the grafted seedling survives.

As can be seen from table 2, the scion selected in this example was grafted onto a strong-growing (rootstock) plant, and a high survival rate of grafted seedlings was obtained, with Crimson sweet, XBM, Yu2, Yu10, Charlston Gray as the test specimen, the survival rate of grafted seedlings was not less than 73%, and the top end vine (top bud) with growing points as the scion, which was the highest and reached more than 92%; secondly, tendrils with two nodes are used as scions, and the survival rate of the grafted seedlings is not lower than 81%; the vine with one node is used as a scion, the survival rate of the grafted seedlings is lower, but the survival rate of the grafted seedlings is not lower than 73%.

(4) Management of field

And (4) planting the survived grafted seedlings in a greenhouse, and performing fine management. Selfing and pollinating until the fruit is mature.

(5) Seed harvesting

Cutting open ripe watermelon fruit, identifying whether the watermelon fruit is tetraploid seed or not through morphology, then washing with clear water and drying in the air to obtain the tetraploid seed which is successfully mutagenized, and can be used for subsequent research. Tetraploid watermelon seed characteristics: increase and thicken, widen hilum, and protrude rhynchus.

Compared with the conventional technology, the invention obviously increases the mutation T₀The generation plant, fruit and seed number greatly improves the tetraploid mutagenesis efficiency, and the comparison result is shown in table 3.

TABLE 3 tetraploid mutagenesis effect of the present invention method and conventional technique

From Table 3, it can be seenCompared with the prior art, the method can greatly improve the mutagenesis efficiency and increase the mutagenesis T₀The number of plants, fruit number and seed number of generations. Specifically, by combining tables 1 and 2, by conventional techniques, Crimson sweet seedlings were treated with 0.2% colchicine instillation to obtain 11 tetraploid T seedlings₀Instead, 80 tetraploid T strains can be propagated by adopting the method of the invention₀Generation, T₀The number of generation plants is increased by more than 7 times, the number of fruits is increased by nearly 9 times, and the number of seeds is increased by more than 8 times; likewise, mutagenesis of the remaining watermelon varieties T₀The number of plants, fruit number and seed number of generations are obviously improved.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Not all embodiments are exhaustive. All obvious changes and modifications which are obvious to the technical scheme of the invention are covered by the protection scope of the invention.

Claims

1. The application of the watermelon tetraploid propagation method in seedless watermelon breeding is to use the diploid watermelon homozygous inbred line as the material and to use colchicine to perform tetraploid induction in the seedling stage; selecting a tetraploid watermelon plant which is successfully mutagenized as a material, taking the vine of the tetraploid watermelon plant as a scion and the strong west graft as a stock, grafting by using a grafting method, and performing grafting according to a management method of a grafted seedling until the grafted seedling survives; planting the surviving grafted seedlings, selfing and pollinating until the fruits are mature;

the scion is selected from a vine with a growing point, or a vine with a node, or a vine with a plurality of nodes;

cutting off a rootstock cotyledon by using a blade at an angle of 30 degrees upwards, cutting off a scion by using a blade at an angle of 30 degrees upwards, and clamping a wound by using a grafting clamp after the rootstock is attached to the scion;

after grafting, covering the grafted seedlings with a plastic film, covering a sunshade net, and shading and moisturizing within 2d after grafting; 3d, starting to uncover the film to release air and give illumination, covering the film after the water drops on the grafted seedlings are dried, and releasing air once in the morning and at night; the time of air release and illumination is sequentially prolonged for the next week until the grafted seedling survives.

2. The use according to claim 1, characterized in that the specific operations of tetraploid induction are: manually breaking the shell of the diploid watermelon homozygous inbred line seed, soaking in warm water for 2h, accelerating germination for 24h at 32 ℃, and sowing; removing seedling apical centers after seedling cotyledons are unfolded, performing tetraploid induction by using colchicine dripping seedlings with mass concentration of 0.2%, dripping 1 drop in the morning and at night, and treating for 6 d.