CN115152445B - Method for artificial hybridization breeding by utilizing Yang Shuxi short flowering branches - Google Patents

Abstract

The invention belongs to the technical field of forest hybridization breeding, and discloses a method for carrying out artificial hybridization breeding by utilizing Yang Shuxi short flowers. The method comprises a whole set of technical methods of stock preparation, stock cultivation, flower branch collection, flower branch treatment, flower branch grafting, management after grafting and the like, effectively improves the availability of stock cultivation, improves the yield of flower branch grafting, shortens the time from flower branch grafting to hybridization pollination, improves the nutrient supply efficiency of flower branches in the later stage of hybridization, and improves the hybridization breeding technology of poplars.

Description

A method for artificial crossbreeding by utilizing the thin and short flowering branches of poplar

technical field

The invention belongs to the technical field of hybrid breeding of forest trees, in particular to a method for artificial hybrid breeding by utilizing thin and short flowering branches of poplar.

Background technique

Germplasm resources are the important genetic and material basis for genetic improvement of forest trees. With the changes of the international situation and the global environment, the export control of germplasm resources abroad is becoming more and more strict, and the number of domestic forest germplasm resources is also decreasing day by day. At present, the protection and utilization of germplasm resources have attracted more and more attention. Poplar hybrid breeding is the most important way to improve poplar, and most of the cultivated varieties at home and abroad are selected through this way. Excellent germplasm resources are an important material basis for creating improved poplar varieties. However, current poplar hybrid breeding is facing a shortage of hybrid parent resources. How to use the flower branches of hybrid parents more economically and efficiently has become a problem that must be solved by scientific and technological workers.

Conventional hybrid breeding of poplar mainly has two methods, one is artificial hybridization on outdoor big trees, and the other is artificial hybridization indoors after the flower branches of the female parent are cut. Around the above two methods, scholars at home and abroad have carried out a lot of research. Zhou Zhongcheng et al. proposed the outdoor plant oblique method and the outdoor cutting branch cutting method, and Shengjun et al. proposed the technology of heating flower branch potted plants to promote rooting. The research team has successively been approved "a method for improving the seed setting rate and quality of poplar cutting branch hydroponic hybrid breeding", "a poplar breeding device and its use method" and "a method for improving black poplar" through preliminary tests. Artificial hybrid breeding method for nutrient supply of female flower branches" and other patented technologies. The above-mentioned patented methods have played a positive role in improving the operation process and procedures, reducing the cost of hybridization, and improving the breeding quality of cutting branches and hydroponics.

But currently facing a new problem in poplar hybrid breeding, that is, sometimes the parental resources are few, and sometimes because the poplar parent tree that intends to collect flower branches is tall, enough flower branches cannot be collected, and sometimes a certain number of flower branches can not be collected. The flower branches are thinner and shorter in length, and the nutrient storage of these flower branches is insufficient. The use of conventional cut branch hydroponic miscellaneous transactions causes a large number of fruits to fall off due to insufficient nutrient supply, which greatly reduces the hybrid seed setting rate. Completely, it is difficult to obtain healthy and normal seedlings, so it is not suitable for cross cutting hydroponics. Under the above background, how to use the collected flower branches with thinner thickness and shorter length for hybridization has become a technical problem that must be solved in order to realize saving and efficient utilization of germplasm resources.

Contents of the invention

In order to solve the problem of high-efficiency hybrid utilization of poplar branches with thinner thickness and shorter length, the invention provides a method for artificial hybridization and breeding by utilizing thin and short flower branches of poplar trees.

Technical scheme of the present invention is as follows:

The present invention provides a kind of method utilizing poplar thin and short flower branch to carry out artificial hybridization breeding, comprises the following steps:

Select cutting seedlings or transplanting poplar as the rootstock, cultivate the side branches of the rootstock to a thickness of 1.0-2.0cm for grafting, control the temperature of the greenhouse during the day at 10-15°C, at night at 5-10°C, and the relative humidity at 50-60%;

Except for the grafting part, the flower branch is soaked with 0.02-0.04% abscisic acid, 0.01-0.02% ethephon, 1-2% potassium sodium tartrate and 2-3% compound amino acid solution, and the soaked poplar thin and short flower branch is grafted on the rootstock , Spray growth regulators at the grafting interface;

On the 1st to 3rd day after grafting, heat the potting container to keep the temperature of the substrate at 23-25°C, and perform auxiliary heating on the grafted part of the flower branch to keep the temperature at 22-24°C; then adjust the daytime temperature of the greenhouse to 20-25°C and night Cultivate at 5-10°C with a relative humidity of 50-60%.

As an embodiment, if cutting seedlings are used as the rootstock, the cultivation method of the rootstock includes: retaining all the germinated buds of the rootstock, and when the sprouted shoots grow to a length of 30-40 cm or more in mid-to-late April, the sprouted shoots are treated. Cut short and keep the lower 2/3 length; timely spray gibberellin and cytokinin on the shoots and leaves to promote the germination of lateral buds; cut off the shoots when the germinated lateral buds grow to a length of 40-60 cm or more, and keep the lower 2/3 length; After cutting off the shoots, the side branches are smeared from time to time, and the lower part of each side branch is strangled at the germination point, deep to the xylem, and paclobutrazol is regularly sprayed until the thickness of the side branches reaches between 1.0 and 2.0 cm.

Preferably, the mass concentration of the gibberellin is 0.05-0.1%, and the mass concentration of the cytokinin is 0.02-0.05%.

Preferably, when the thickness of more than 90% of the side branches from the bottom to the top of the rootstock reaches 1.0-2.0 cm, the leaves are removed, sealed and placed in a refrigerated controlled atmosphere warehouse to inhibit the thick growth of the side branches.

As a kind of implementation mode, if transplant poplar as rootstock, select 1-3 year-old poplar seedlings with close genetic relationship with female and male flower branches, and the selection standard for a single plant is 1.0-2.0 below the trunk height of 2-2.5m. The more annual side branches of cm thickness, the better.

Preferably, the transplanted poplar is truncated from a height of 2 to 2.5 m, transplanted into a container with soil balls, filled with peat and soil at a volume ratio of 2:1, and filled with 100 to 150 mg/L of indole acetic acid and 100 ～150mg/L naphthaleneacetic acid in equal volume ratio, and the resulting solution is used to irrigate the roots once until the soil is saturated.

Preferably, the male flower branches are first grafted, and the female flower branches are grafted when the infructescence begins to germinate.

Preferably, the growth regulator includes the following components in weight percentage: 0.02-0.03% of naphthaleneacetic acid, 0.01-0.02% of gibberellin, 0.01-0.02% of sodium nitrophenolate, 0.02-0.03% of polyvinyl alcohol and compound amino acid 2 ~3%.

Preferably, the short flowering branches of the poplar have a thickness of 0.5-0.8 cm and a length of 4.0-10.0 cm.

Preferably, the grafting is carried out by cutting grafting, the grafting port is sprayed with a growth regulator and bound with a grafting film, and the flower branches are all bound in the film except flower buds.

Compared with the prior art, the present invention has the following technical effects:

The present invention aims at the problems that the flower branches collected in poplar hybrid breeding are relatively thin and short in length and cannot be used in normal cut branches for hydroponic use, and the survival rate of flower branches in common grafting techniques is low, and provides a method for artificial hybrid breeding using thin and short flower branches of poplar. Methods. The method of the present invention can effectively improve the utilization efficiency of rootstock cultivation, improve the survival rate of flower branch grafting by 23.5-31.0% from the whole set of technical methods such as rootstock preparation, rootstock cultivation, flower branch collection, flower branch treatment, flower branch grafting, and post-grafting management. The time from grafting of flower branches to cross pollination is shortened by 3-6 days, the nutrient supply efficiency of flower branches in the later stage of hybridization is improved, and the hybrid breeding technology of poplar is improved.

Detailed ways

The technical solution of the present invention will be further described in detail below in conjunction with specific embodiments, and the technical solution of the present invention includes but is not limited to the following examples.

In order to solve the problem of high-efficiency hybridization of poplars with thinner thickness and shorter length, the present invention provides a complete set of technical methods from rootstock preparation, rootstock cultivation, flower branch collection, flower branch treatment, flower branch grafting, and post-grafting management.

Example

A method for artificial crossbreeding by utilizing the thin and short flowering branches of poplar

1. Rootstock preparation: the thicker the better the stock for conventional grafting, in the artificial cross breeding method of the present invention, in order to improve the nutrient supply of short flowering branches, the stock needs to be cultivated in advance.

According to the cross-breeding parent-combination plan, the names of the female and male flower branch varieties are first determined. If the preparation time is sufficient, the cuttings of the same variety are selected for cutting seedlings one year in advance before starting cross-pollination. The length of the cuttings is 30-40cm, and the thickness is 1.5-2.0cm. Cuttings are cut in early March. Before cutting, soak in a 1:1 mixture of indoleacetic acid and naphthaleneacetic acid at 50-100mg/L for 12-24h. Quick dip disinfection. As an implementation, the cutting container has an inner diameter of 50-60 cm and a depth of 60-70 cm. When conditions permit, a bottom plate with a four-way steering at the bottom can be configured to facilitate later movement. As an implementation method, when cutting, the cuttings are oriented east-west, and inclined 30-40° to the east or west, and 2-3 buds are kept exposed outside the substrate, which is conducive to the germination and growth of all exposed buds, so as to produce more branches. Rootstock for grafting. As an embodiment, the substrate used for cuttings is peat and soil mixed in a volume ratio of 2:1.

If the hybridization plan is too late for cutting seedlings, you can choose 1-3 year old poplars that are closer to the female and male flower branches in late October to mid-November before the collection of flower branches (generally in early February in North China). The seedlings of tree species are used as rootstocks. It should be selected in the side rows of single plants in forest land or nursery land with convenient transportation. The selection standard for a single plant is that the annual side branches with a thickness of 1.0 to 2.0 cm below the trunk 2 to 2.5 m have as many as possible. As a preferred embodiment, after selection, it can be truncated from a height of 2 to 2.5m, and transplanted into a container with a soil ball. The inner diameter and depth of the container should be more than 10cm larger than the soil ball, and the volume ratio of the extra space should be 2:1. Fill it with peat and soil, and use 100-150 mg/L indole acetic acid and 100-150 mg/L naphthalene acetic acid in equal volume ratios to irrigate the roots once until the soil is saturated, so as to facilitate the timely recovery of the root system. After transplanting, the side branches should be wrapped with plastic film to prevent water loss in winter. After transplanting, the annual side branches with a thickness of 1.0-2.0 cm should be pruned. After pruning, the side branches should be fully lignified and evenly distributed on the main trunk.

2. Rootstock cultivation: rootstock cultivation technology is an important technical link to improve the quantity and quality of short flower branch grafting.

For rootstocks propagated by cuttings, keep all the germinated buds, and when the sprouts grow to a length of 30-40 cm or more in mid-April, adjust the growth direction of the sprouts by pulling the rope to make them "happy" and uniform in different directions. distribution, at the same time cut the sprouted bar short, keep the lower 2/3 length, and at the same time spray the sprouted bar and the leaves between 9:00 and 10:00 in the morning. and cytokinin with a mass concentration of 0.02-0.05%, to promote the germination of lateral buds. When the germinated side buds grow to a length of 40-60 cm or more, cut off the shoots in time, and keep the lower 2/3 of the length. After cutting off the shoots, wipe the buds on the side branches from time to time to prevent them from re-germinating side buds, and hang them with soft iron wire to germinate on each side branch. At the lower part, deep to the xylem, and spray paclobutrazol (mass concentration 0.05-0.1%) every 15-20 days to promote the thickening and growth of side branches, observe the growth thickness of side branches at any time, and the thickness of side branches is most suitable between 1.0-2.0cm Make rootstock for grafting. If the thickness of more than 90% of the side branches from the bottom to the top of the branch has reached the range of 1.0-2.0cm, it can be suppressed by removing the leaves and sealing them into a refrigerated air-conditioned warehouse (3-5°C, air humidity 60-70%) The side branches grow thickly to improve the convenience of the subsequent short flower branch grafting operation and the survival rate of grafting.

3. Collection of flower branches: The collection of flower branches should be carried out before the sap flows. The collection time in North China is generally at the end of January and the beginning of February. When collecting flower branches, choose the branches that grow robustly in the middle and upper part of the canopy and are free from diseases and insect pests. In principle, it is required that the thickness of male flower branches is between 1.5 and 2.5 cm, and the thickness of female flower branches is between 2 and 3 years. When there are not enough flowering branches, the flowering branches that can be collected should be collected as much as possible first, and brought back indoors for classification and disposal. When sorting and disposing, according to different varieties, the thickness and length are used as the standard to place them separately, so as to improve the work efficiency in the next step of grafting.

4. Treatment of flower branches: If the collected flower branches cannot be grafted immediately, the female flower branches can be sealed with plastic film as a whole, and first placed in a cold storage at 2-3°C for 5-7 days in order to maintain the vitality of flower buds and improve the later flowering and development vitality. Keep the branches with flower buds about 120cm long for the female and male flower branches, and trim the flower branches according to the normal branch cutting hydroponics procedure, remove the elongated branches, and keep all the flower buds after removing the diseased, weak and defective flower buds. Thinner (0.5-0.8cm) and shorter (4.0-10.0cm) flower branches are collected and sealed separately for grafting, so as to improve the utilization efficiency of flower branches and improve the seed setting rate of hybrid breeding. Each flower branch hangs a label, indicating the species, collection time and other matters.

5. Flower branch grafting: Before grafting, move the rootstock into the greenhouse, the room temperature is 10-15°C during the day, 5-10°C at night, and the relative humidity is 50-60%, so as to facilitate the rapid growth and development of flower buds. The rootstocks to be grafted with different male parents should be placed separately to prevent pollen contamination. On the same rootstock, the female flower branches of different female parents and the male flower branches of the same male parent can be grafted. . Except that the grafted part of the lower end of the flower branch is not soaked before flower branch grafting, abscisic acid with a mass concentration of 0.02-0.04%, ethephon with a mass concentration of 0.01-0.02%, potassium sodium tartrate with a mass concentration of 1-2%, and potassium sodium tartrate with a mass concentration of 2-0. Soak in 3% compound amino acid mixture for 15-30 minutes, and the mixing ratio is equal volume ratio. After soaking in the mixed solution, the germination time of flower buds can be delayed to 3-5 days after the healing of the grafting site, and the pollen vigor of male catkins and the nutrient supply of female flowers after pollination can be effectively improved.

As an embodiment, the grafting method is used for grafting, and the growth regulator is sprayed on the grafting interface after grafting. The mass percentage of the growth regulator components is composed of 0.02-0.03% of naphthaleneacetic acid, 0.01-0.02% of gibberellin, and 0.01-0.02% of sodium phenate, 0.02-0.03% of polyvinyl alcohol and 2-3% of compound amino acid are mixed according to equal volume ratio. Spraying the growth regulator can shorten the healing time of the graft joint by 4-6 days, and increase the healing degree of the graft joint by 32%-45% compared with that without spraying. After spraying, tie it with grafting film, and all flower branches except flower buds should be tied in the film to prevent water loss.

6. Management after grafting: After grafting, the room temperature should be 10-15°C during the day and no lower than 5-10°C at night, and the relative humidity should be 50-60%. Low temperature can reduce the physiological activity of flower buds and prevent the consumption of their own flower branch nutrients. Appropriate air humidity can prevent flower buds from dehydration. The two technical parameters are to improve the supply of all nutrients for the development of fruit flocs after pollination. On the 1st to 3rd day after grafting, continuously heat the potting container with an electric blanket or electric heating wire to keep the temperature of the substrate at 23-25°C, so as to increase the ambient temperature of the root system of the rootstock, accelerate the root system vitality and nutrient absorption and utilization efficiency; use warm treasure Auxiliary heating is carried out on the grafted part of the flower branch to keep the temperature at about 23°C. Afterwards, adjust the room temperature to 20-25°C during the day, 5-10°C at night, and 50-60% relative humidity to improve the healing of the cambium at the grafted part, ensure that the grafted flower branch obtains exogenous nutrient supply from the rootstock as early as possible, and improve the development of infructescence. The rest are carried out according to the procedures of pollen collection, pollination and fruit harvesting in cross-cutting hydroponic hybridization.

Experimental example

This experimental example provides L324 poplar (Populus deltoides 'L324') (female parent) x Lulin No. 9 poplar (Populus deltoides 'Lulin Jiuhao') (male parent) short flowering branches for artificial cross breeding. The specific implementation results are as follows:

On February 13, 2019, short flower branches of Populus Lulin 9 (male plant) were grafted in the greenhouse of Jinan Academy of Forestry, Shandong. On February 20, 2019, short flower branches of Poplar L324 (female plant) were grafted. The rootstocks used for grafting were all It is Poplar Zhonghe No. 1 (P.deltoitescv.'Zhonghe-1').

Each 15 pots of male and female flower branches, 1 stock in each pot, 8 to 11 side branches can be grafted for each stock, and the grafting method is the method of the embodiment of the invention, that is, the flower buds use abscisic acid with a mass concentration of 0.02%, and a mass concentration of 0.01% % ethephon, potassium sodium tartrate with a mass concentration of 1%, and a compound amino acid mixture with a mass concentration of 2% for 15 minutes. Spray the mixture of 0.02% naphthaleneacetic acid, 0.01% gibberellin, 0.01% sodium nitrophenolate, 0.02% polyvinyl alcohol and 2% compound amino acid in equal volume ratio to the grafting site.

There are 6 pots of male and female flowering branches, and the number of side branches that can be grafted per rootstock is 8-10. Conventional grafting without any treatment is used as a control.

After grafting, they were all in the greenhouse, keeping the indoor temperature at 23°C during the day, 8°C at night, and a relative humidity of 50%.

On February 27, 2019, the investigation was conducted on the development of the male flower branch of the grafted Lulin 9 poplar, and on April 10, 2019, the fruit-setting development of the grafted L324 poplar female flower branch was investigated. The result is as follows:

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (7)

1. a kind of method that utilizes poplar fine and short flower branch to carry out artificial hybridization breeding, it is characterized in that, may further comprise the steps: Select cutting seedlings as the rootstock, cultivate the side branches of the rootstock to a thickness of 1.0-2.0 cm for grafting, control the temperature of the greenhouse during the day at 10-15°C, at night at 5-10°C, and the relative humidity at 50-60%; Except for the grafting part, the flower branches are soaked with a mass concentration of 0.02-0.04% abscisic acid, 0.01-0.02% ethephon, 1-2% potassium sodium tartrate and 2-3% compound amino acid solution, and the soaked short flower branches of poplar are grafted Spray the growth regulator on the rootstock and grafting interface; On the 1st to 3rd day after grafting, heat the potting container to keep the temperature of the substrate at 23-25°C, and perform auxiliary heating on the grafted part of the flower branch to keep the temperature at 22-24°C; then adjust the daytime temperature of the greenhouse to 20-25°C and night Cultivate at 5-10°C with a relative humidity of 50-60%; The thin and short flowering branches of the poplar have a thickness of 0.5 to 0.8 cm and a length of 4.0 to 10.0 cm; The cultivation method of the rootstock comprises: retaining all germinated buds of the rootstock, and short-cutting the sprouted strips when the sprouted strips grow to a length of more than 30 cm in the middle to late April, and keeping the lower 2/3 length; The leaves are sprayed with gibberellin and cytokinin to promote the germination of lateral buds; when the germinated lateral buds grow to a length of more than 40cm, the shoots are cut off, and the lower 2/3 length is reserved; The lower part is hanged, deep to the xylem, and paclobutrazol is sprayed regularly until the thickness of side branches reaches between 1.0 and 2.0 cm. 2. The method according to claim 1, characterized in that the mass concentration of the gibberellins is 0.05-0.1%, and the mass concentration of the cytokinins is 0.02-0.05%. 3. The method according to claim 1, characterized in that, when the thickness of more than 90% of the side branches from the bottom to the top of the branch reaches the range of 1.0 to 2.0 cm, the leaves are removed, sealed and put into refrigerated air. Adjusting the pool inhibits the growth of lateral branches. 4. The method according to claim 1, characterized in that, the rootstock is a transplanted poplar, and the 1 to 3-year-old poplar variety nursery stock with a close genetic relationship with the female and male flower branches is selected, and the selection standard for a single plant is the trunk The more annual side branches with a thickness of 1.0 to 2.0 cm below the height of 2.5 m, the more the better; the transplanted poplar is truncated from a height of 2 to 2.5 m, transplanted into a container with a soil ball, and peat and Fill with soil, mix 100-150 mg/L indole acetic acid and 100-150 mg/L naphthalene acetic acid in an equal volume ratio to form a solution, and irrigate the roots once with the obtained solution until the soil is saturated. 5. The method according to claim 1, characterized in that the male flower branches are first grafted, and the female flower branches are grafted when the infructescence begins to germinate. 6. The method according to claim 1, characterized in that, the growth regulator comprises the following components in percentage by weight: 0.02 to 0.03% of naphthaleneacetic acid, 0.01 to 0.02% of gibberellin, and 0.01 to 0.02% of sodium nitrophenolate , polyvinyl alcohol 0.02-0.03% and compound amino acid 2-3%. 7. The method according to claim 1, characterized in that, the grafting is carried out by cutting grafting, the grafting port is sprayed with a growth regulator and bound with a grafting film, and flower branches are all bound in the film except flower buds.