What are the propagation methods for jujube trees? A detailed explanation of common seedling techniques

Jujube propagation is mainly by division and grafting. Among these, grafting mainly includes woody bud grafting and stem grafting. Grafting techniques can be summed up in a six-character key: “fresh” means the scion should be kept fresh with no water loss. “flat” means the cut surface of the scion should be flat. “accurate” means the cambium of the scion and rootstock should be aligned. “tight” means after grafting it should be wrapped and tied tightly. “fast” means the operation should be done quickly. “moist” means after grafting it should be buried in soil or covered with a plastic bag to maintain moisture.

1. Grafting

The main grafting methods are woody bud grafting and stem grafting (stem grafting mostly uses bark grafting). The key technical points of grafting can be summed up in a six-character key: “fresh”, the scion should be kept fresh with no water loss. “flat”, the cut surface of the scion should be flat. “accurate”, the cambium of the scion and rootstock should be aligned. “tight”, after grafting it should be wrapped and tied tightly. “fast”, the operation should be done quickly. “moist”, after grafting it should be buried in soil or covered with a plastic bag to maintain moisture. At the same time, 5-7 days before grafting, irrigate the rootstock nursery to make it easier for the bark to separate.

2. Root cutting

Select own-rooted plants of superior varieties. Before sprouting, dig a trench around the outer edge of the canopy 30-40 cm wide and about 50 cm deep, cut roots with a diameter of 2 cm or less, apply organic fertilizer in the root-cutting trench, and then backfill immediately. During the growing season, root suckers can emerge. In the second spring, dig out the root suckers, treat them with ABT rooting powder or other hormones, replant them in the nursery, and cultivate strong seedlings.

3. Root cuttings

In late autumn, in combination with autumn plowing, collect roots from vigorous jujube trees, cut them into root segments 20-30 cm long and 1-4 cm in diameter, and store them in sand in a cellar. In the second spring, open a trench for seedling raising, insert the root segments into the trench at a 45-degree angle, with 2 cm exposed above the ground, and water immediately after insertion. Treating the root segments with rooting hormones and covering with plastic film gives even better results.

4. Tissue culture

As of 2008, Gansu Province had achieved results in tissue culture seedling raising. The Horticulture Department of Gansu Agricultural University and scientific research and extension departments in Wuwei, Jingtai, Jiuquan and other places already had the technology, equipment and conditions for producing tissue-cultured seedlings.

Through analysis and research on several factors affecting the in vitro rapid propagation of jujube, the most suitable explant for its in vitro rapid propagation was selected - the young shoot stem segment from early spring hydroponics. The initiation medium was H94 + IBA 0.1 mg/L + NG 15 mg/L solid medium with H66 nutrient solution added for solid-liquid two-phase culture. The subculture medium was H66 + NG 20 mg/L + IBA 0.1 mg/L. After 30 days of subculture, the average multiplication coefficient was 4. The rooting medium was H94 + NG 3-8 mg/L + IAB 0.1 mg/L, with a rooting rate of 90%. After culturing in the tissue culture room for 20 days, place in a solar greenhouse for about another 10 days, then open the bottle stopper and harden the seedlings for 3-4 days, transplant using the Qinghe sand transition transplanting method, and the survival rate can reach 96%.

When test-tube plantlets have grown on the rooting medium for about 20 days, reach a height of 4-6 cm, and have more than three roots, place them in a solar greenhouse for about another 10 days, open the bottle stopper and harden the seedlings for 3-4 days, and transplant them into a disinfected seedbed (the seedbed method is the same as the green shoot cutting seedbed method in the experimental method). The transplanting depth is 3 cm, and the survival rate can reach 96%.

Using the root system of tissue-cultured plantlets as cutting material makes it easy to survive. In field cuttings, however, the conditions are harsh: the thickness must reach more than 1 cm and the length 15-20 cm; even with rooting agent treatment, the rooting rate is still very low.

5. Cuttings

Cutting process: before cutting, first moisten the sand bed. The standard for moistening is that after holes are made in the sand bed, the holes do not collapse. When cutting, use a small wooden stick to make holes in the sand bed while dipping the cuttings in slurry and inserting them. The diameter of the small holes should be larger than the diameter of the cuttings after dipping in slurry, so as to avoid the medicinal solution being squeezed off by the walls of the small holes and reducing its efficacy. The cutting depth is about 3 cm. Too deep easily causes basal rot, while too shallow causes the cuttings to tip over and the roots to be exposed after rooting. After cutting, the holes should be pressed tight so that the river sand and cuttings are closely combined.