Propagation techniques of Actinidia chinensis seedlings

Propagation techniques of Actinidia chinensis seedlings

1 sowing and raising seedlings

Collect the fruit of wild soft jujube kiwifruit, wait for it to soften, take the seeds by the method of scrubbing, and dry in the ventilated place. Before sowing, the seeds were soaked in clean water for 1-2 days, and mixed with fine river sand, the amount of river sand was 1-2 times that of seeds. The water content of the sand can be separated by holding tightly without dripping and letting go of the sand mass. The absolute water content is 5%, which is beneficial to the absorption and respiration of seeds. Then put it in a wooden box and store it under the condition of 0 ℃. Ten days before sowing, the seeds were taken out of the sand and soaked in clean water for 1 day and 2 days to change water once a day. After 20-25 ℃ moisturizing and accelerating germination, most of the seeds could be sown when the seed coat was cracked and radicle was exposed in 5-10 days.

2 hardwood cuttings

Hardwood cuttage is a method of raising seedlings by using one-year-old lignified branches, which belongs to asexual reproduction and needs to be produced in greenhouse or open cold greenhouse. Combined with winter pruning, strong and well-developed branches are retained and bundled into bundles. Pruning is usually carried out three or nine days or 8 weeks before the sap flows. For example, cutting in greenhouse can be carried out from January to February, such as cutting in cold shed, the base should be buried in wet sand, placed under the condition of 0 ℃, and stored before and after Qingming Festival to ensure sufficient cold demand and pass the dormancy period. Before cutting, the branches were placed under 5 ℃ for 48 h to break dormancy. The cuttings generally leave 10-15 cm, and each branch had better leave more than 2 bud holes. The incision was cut at an angle of 45 °from the upper part of the upper bud eye and 1.5 cm from the lower part of the lower bud eye. The section should be smooth. The basal 2-3 cm was immersed in indolebutyric acid solution with a concentration of 100-150 mg/kg for 24 h. Soak it with rooting agent and insert it into the culture soil. Distinguish between the upper part and the lower part of the cutter, can not be reversed. The insertion depth should be 2pm and 3, and the cuttings should be watered once, preferably disinfected with carbendazim solution. The upper incision is sealed with paint or wax to prevent pulp. The rooting was promoted under the condition of room temperature about 5 ℃ and ground temperature 25 ℃. Generally, it can take root in about 15 days.

The culture soil of hardwood cuttings must be loose and breathable, which is conducive to root growth. It can be mixed with fine river sand and sawdust (except pine sawdust, which contains too much oil) and mixed with soil in the proportion of 1 ∶ 5. The experimental results show that the rooting rate of furnace ash mixed with soil is 13.6% higher than that of fine river sand, and the root system is well developed, so it is a good cutting substrate. At the same time, the improvement of ground temperature is very important for rooting, generally heating up the hot line buried in the cultivated soil, which is simple and convenient, labor-saving and labor-saving.

3 Greenwood cuttings

Greenwood cutting is a propagation method of raising seedlings by using new shoots that have reached semi-Lignification. This method can raise seedlings in the open field, has high propagation efficiency and low production cost, and is a conventional method for rapid seedling breeding. In the middle and last ten days of June, combined with summer pruning, the sturdy and well-developed branches were taken as cuttings, cut flat at 1.5 cm from the upper part of the bud eye, and the section should be smooth. The lower part was cut at an angle of 45 °. If only one leaf is left, the leaf can also be cut off to reduce water transpiration, which is beneficial to rooting. The cuttings were soaked in 1 000 ~ 2 000 mg/kg naphthalene acetic acid solution for 1.5 min, then inserted obliquely into the seedling bed, and the suitable depth was 1.5 cm for exposed bud eyes. River sand or fine furnace ash was used as rooting substrate with a thickness of about 20 cm. Need to pay attention to two points, first, the nursery bed to make a high bed to prevent Rain Water flooding seedlings, causing cuttings rot. Second, because the cuttings have not yet formed roots, the water supply is not high, and leaf transpiration is easy to cause wilting, so higher air humidity should be ensured. The bed should have good air permeability and suitable humidity, and it is appropriate to maintain 60% to 80% of the maximum water holding capacity of the soil.

A shade shed shall be built on the seedbed. Every 1.5 m is provided with a frame arch with a height of 0.6 m and a sunshade net with a light transmittance of 50%. In sunny days, spray water with a fine spray bottle every 30 min, and each time the water is semi-atomized. Keep the leaves moist often and there is no need to spray more. If the temperature is too high or windy, the frequency of water spraying should be increased appropriately. After cutting for 30 days, the amount of spraying water was reduced, and the rooting was checked at the same time. When the cutting base produced 5-6 2-3-cm long roots, the spraying was stopped and the shading net was removed. The seedlings started at the end of October and went into the cellar for sand storage. If the cutting time is late and the degree of Lignification is not high, we should pay attention to the cold treatment of overwintering [Yoshanhua Yao].

4 tissue culture

Tissue culture is a propagation method which makes use of the regeneration function of plant organs, tissues or cells in vitro to develop into complete plants through artificial culture, and has the characteristics of maternal heredity [3]. Tissue culture is not limited by season, less consumables, large and fast reproduction, which is an important means of large-scale seedling production. However, because of its high requirements for production conditions, it is not suitable for farmers to breed on their own.

Collect new shoots from May to June, rinse them with clean water for 10 min, disinfect them with 75% alcohol for 20 s, rinse with sterile water for 4 times, disinfect them with 0.1% liter of mercury for 8 min, rinse with aseptic water for 4 times, dry them with sterile paper, and inoculate them on the sterilized induction medium. The buds were cultured on the induction medium for 30 days. The induced buds were divided into several small bud clumps, and the shoots growing more than 2 cm were connected to the rooting medium and rooting could take place after about 15 days. The rooting seedlings can not be transplanted until the seedlings are refined.

5 pressing strip

Striping propagation is a way of propagation in which a part of the branches of the mother plant are pressed into the ground to promote it to take root and then breed into new plants. Its advantage is that the seedlings are not separated from the mother during the growing period, the nutrition supply is sufficient and the growth is exuberant. This method is simple, fast and easy to master. After sprouting in spring, when the new shoot grows to about 15 cm, dig a hole about 15 cm deep next to the mother plant, fold the semi-lignified shoot continuously, press it in the pit, fill and water it. At the end of October in autumn, the strips were separated from the mother plant to form seedlings with their own roots. If you press mature branches, it is best to ring-cut the branches buried in the soil, cut off the phloem and promote rooting [4].

6 hard branch grafting

Cleavage is carried out on Lignified branches in spring. Because the pith of soft jujube kiwifruit is large and empty, the grafting is not easy to survive. The survival rate of grafting is high in spring and can come out of the nursery in the same year. The grafting time in spring is usually 10 days before the Qingming Festival. In order to prevent bleeding after grafting, root cutting can be taken on the same side of the grafting.

The one-year-old branch of the superior variety to be planted was selected as the scion, cut at 1 cm above the scion bud, cut symmetrically at 2 cm below the scion bud and cut into a wedge. The rootstock is cut off in a smooth and straight part, and then cut longitudinally in the middle of the pith of the cross section to insert the scion and align with the cambium of the rootstock. If the thickness of the rootstock is not consistent with that of the scion, aim at one side of the forming layer, tie it tightly with a plastic strip, and only expose the axillary bud, and then wrap it around the upper section of the scion with plastic strip to form a cap to protect the scion. Remove the new buds from the rootstock in time. If the grafting is successful, the scion can sprout in 10 days.

7 green branch grafting

Select the sturdy semi-lignified shoots from the rootstock, leave 2-4 leaves, and cut them 2 cm from the base of the uppermost leaf. The scion should choose the semi-lignified shoots of excellent varieties to grow and thrive, and the tender shoots are not easy to survive. Remove the leaf, leave the petiole, cut at 0.5 cm above the scion bud, leave 2 cm under the bud, and cut it into a double bevel wedge. The bevel should be smooth and uniform. Make a longitudinal cut in the middle of the rootstock, insert the scion, align with the cambium of the rootstock, fasten it with a plastic strip, expose only axillary buds and petioles, and wrap it around the upper section of the scion with plastic strip to form a cap to protect the scion from water loss.

Attention should be paid in the process of grafting: plastic strips must be tied tightly, do not leak seams, to prevent water and air permeability, but not too tight. Attention should be paid to adequate water supply and keeping the soil moist before and after grafting. After budding, remove the plastic strip in time.