How to Quickly Propagate Jujube Trees? A Detailed Guide to Fast Propagation Techniques in Cultivation

Spring is a good season for propagating jujube trees. As for the fast propagation techniques in jujube cultivation, they mainly focus on the two methods of cutting and grafting. Below is a detailed explanation of these two propagation techniques for jujube trees.

I. Grafting propagation techniques for jujube cultivation

1. Cultivation of rootstock

(1) Cultivation by retaining suckers

Sucker retention cultivation makes use of the characteristic that jujube trees have a strong ability to sprout root suckers, and obtains seedlings by retaining the root suckers that naturally sprout around jujube trees in an existing jujube orchard. The advantage of this method is that it is simple and easy to carry out, but the number of seedlings produced is small, the seedlings are not uniform, the root system is poorly developed with few fine roots, and the survival rate after planting is low.

(2) Cultivation by trenching and root cutting

This method makes use of the trait that wounded jujube roots more easily produce root suckers. A trench is dug around the jujube tree to cut the root system and promote the sprouting of root suckers. The advantages of this method are a large number of seedlings and high seedling quality. The specific procedure is: before jujube trees sprout in spring, dig a ring-shaped trench or a strip-shaped trench along the direction of the jujube rows at a distance of 3 to 5 m from the trunk outside the canopy, with a depth of 40 to 50 cm and a width of 30 to 40 cm, and cut off fine roots with a diameter of less than 2 cm. The cut surfaces of the roots should be smooth. Then fill in loose moist soil to cover all cut roots, so as to facilitate wound healing and the production of root-sucker seedlings. When the root-sucker seedlings grow to 20 to 30 cm, remove the weak and keep the strong, leaving 1 or 2 plants per root-sucker clump.

(3) Cultivation by returning to the nursery for seedling raising

This method is a seedling-raising method in which scattered natural root-sucker seedlings in the field that do not meet seedling quality requirements, or root-sucker seedlings produced after trenching, are centrally transplanted into a nursery for continued cultivation and are only released from the nursery after reaching seedling quality standards. Because the small seedlings undergo one transplanting, this method is also called secondary seedling raising. Its advantages are convenient management, uniform seedlings, well-developed root systems, and a high survival rate after planting when released from the nursery. The nursery land should be selected as a plot with loose soil, relatively strong fertility, soil salt content not exceeding 0.2%, good drainage, and irrigation conditions. The planting spacing is generally 12×60 cm, and water should be applied promptly after planting. In addition, timely topdressing, intertillage and weeding, and removal of sprouts and suckers should be carried out. Generally, after 1 to 2 years of cultivation in the nursery, the seedlings can be released.

2. Grafting

(1) Collection and treatment of scions.

Scions should be collected from a scion orchard of superior varieties or from robust superior-variety trees in production. For cleft grafting, use vigorous 1- to 3-year-old primary branches of the jujube head or 2- to 3-year-old secondary branches. Generally, in combination with winter pruning, scions are collected before budbreak. Scions used for bud grafting should be collected and used immediately; after collection, the secondary branches and leaves are cut off to reduce water evaporation. For transporting scions, use straw bags or wet gunny sacks for packaging, and pay attention to moisture retention and temperature maintenance during transport.

For reserved scions, jujube branches collected during the dormant period need to be cut into branch sections with a single bud or double buds. Melt paraffin in a container, quickly dip each scion once in the melted paraffin liquid; when the quantity is large, use a strainer to quickly dip the scions in the paraffin liquid, then immediately spread them out, that is, seal the scions with wax. The suitable wax temperature is 90°C to 105°C. If the temperature is too high, the scions are easily scalded; if the wax temperature is too low, the wax layer is too thick and easily peels off. The waxed scions can be placed in cardboard boxes or plastic bags and stored in a freezer or cold storage at 0°C to 5°C, then taken out for grafting before grafting in spring.

(2) Grafting methods

Jujube grafting methods include cleft grafting, cut grafting, and bark grafting, generally carried out when sap is flowing (around early April).

(3) Management after grafting

After jujube grafting, check the survival rate promptly, and re-graft promptly if problems are found. For branch grafting, checking survival mainly depends on whether buds sprout and whether the color of the scion is bright. If the scion is found to have obvious water loss and wrinkled skin, or wilting after sprouting, it indicates that grafting failed and re-grafting should be carried out. Do a good job of removing sprouts. Jujube seedlings grow relatively fast and are easily broken at the graft union in strong winds. When the jujube seedling is about 30 cm tall, set up a support to tie the seedling, and at the same time remove the plastic strip or other binding material at the graft union. Strengthen fertilizer and water management and pest and disease control.

II. Cutting propagation techniques for jujube cultivation

1. Laying sand and building the bed

Choose a local site that is sheltered from the wind, faces the sun, has relatively high terrain, and has water and power sources to build a sand bed, about 10 cm thick. The area of the sand bed should be determined according to demand. However, the sand bed must have excellent drainage and aeration. Also install active intermittent misting equipment. If there is a power outage, shade net equipment should be added to protect the safety of the cuttings.

2. Collecting shoots and cutting

Collect shoots and carry out cutting from June to September. Select root-sucker seedling side branches, 3-year-old young seedling trees, or young grafted seedlings, etc., and cut semi-lignified side branches as cuttings. Branches and shoot tips that are too tender should be cut off, or before collecting shoots, first pinch off the terminal buds of the tender branches to increase the degree of lignification of the tender branches, so as to enhance the rooting ability of the cuttings.

Pruning should be carried out in the morning, at dusk, or on cloudy and rainy days, and the branches must be protected from damage. Cut cuttings 10 to 12 cm long, retaining 2 compound leaves and 4 to 6 leaflets. After spraying the cut cuttings with a fungicide for sterilization, soak the base in a 100 mg/kg ABT No. 1 rooting powder solution for 2 to 4 hours, then insert them for cutting. The spacing is 4 cm×6 cm, and the cutting depth is about 3 cm. Note that while cutting, misting should be carried out to maintain moisture.

3. Seedbed management

Using active intermittent misting technology, control the seedbed temperature at about 26°C, with the maximum not exceeding 30°C, and maintain high humidity above 90%. Generally, root primordia form 10 days after cutting, and roots can reach about 5 cm after 20 days. During the rooting management period, spray the seedbed with 800-fold chlorothalonil fungicide once about every 7 days to prevent the occurrence of decay disease.

After rooting begins, foliar topdressing should be carried out, spraying once every 3 to 5 days, such as spraying 0.2% urea and potassium dihydrogen phosphate solution, or spraying leaves with a 10 mg/kg rooting powder solution to increase the rooting rate. For rooted seedlings cut in September