How to propagate Kapok

Grafting

Rootstock cultivation

Kapok seeds mature and can be harvested in April to May . Because the seeds have a high oil content and are easily spoiled and lose their germination ability, it is generally required to be sown in time in the same year after harvesting.

Seedlings are raised in the seedbed by row sowing and broadcast sowing. The row spacing of the row sowing is 20 cm and the depth is 5 cm. Seeds are sown in the furrows. Cover with 2 cm of soil and cover the topsoil with grass. The seeds will start to germinate 6 to 7 days after sowing and will be basically fully grown in 13 to 15 days. After the seedlings emerge from the soil, loosen the soil and weed in time, thin out the seedlings and weed appropriately, and pay attention to disease and pest control. When the seedlings are 4 to 5 cm tall and have more than two primary leaves , they can be moved into nutrient bags. When the seedlings are about 40 cm tall, they can be transplanted to cultivate large seedlings. When the seedlings have a breast diameter of 1 to 115 cm, they can be grafted.

Grafting time

It is best to graft kapok in February, March , June and July . The temperature rises quickly from February to March , and the kapok trees begin to sprout and grow branches, and the grafting survival rate is high at this time . The high temperature in April and May can easily cause the scion to dry out. June to July is the rainy season in Panzhihua , and the temperature drops. Grafting should be done away from rainy days.

Selecting scion

Select two-year-old, healthy, full-grown, disease- and insect-free branches that have not flowered yet from flowering kapok mother trees as scion grafts. The selected scion diameter is required to be between 0.17 and 1.2 cm, and the bud spacing is 1 to 2 cm. The leaves of the collected branches should be cut off immediately to reduce the water loss of the branches, and the branches should be wrapped with a wet towel and placed in a cool place. It is best to use them immediately after picking. When the scion needs to be stored for several days, its two ends can be sealed with paraffin and buried in the sand bed. The sand layer should be 4 to 6 cm thick, and attention should be paid to moisture retention and ventilation.

Grafting method

It is better to use single bud grafting when grafting kapok. Experiments have found that no matter how many buds are left on the scion, after the first bud sprouts and shoots, the germination of the remaining buds will be inhibited.

When grafting, first cut the scion. The method is: select a full bud on the scion, and start cutting a flat surface with a slight or no wood part 0.15 cm below the back side, with a length of 1.5 to 2 cm, and then cut a 45° oblique section on the back side, and cut it off 1 cm above the bud . The scion is 4 cm long . For rootstock seedlings, the rootstock should be cut 15 cm above the ground , and a longitudinal cut should be made on the smooth surface of the rootstock, with a length of 1.15 to 2 cm, preferably with a slight touch of wood . Insert the cut scion into the grafting port, align the cambium on both sides and make close contact, with the upper end of the scion exposed. Finally, use plastic film to tie it tightly from bottom to top, and only wrap the bud of the scion with a layer of grafting film, which makes it easy for the film to break automatically after the grafting is successful.

Management after grafting

Kapok young leaves

[Re-grafting] The survival status can be checked 10 to 15 days after grafting. If the buds are fresh and fall off when the petiole is lightly touched, it indicates that the graft has survived; if the scion turns brown, the petiole is not easy to fall off, and the scion becomes soft when squeezed, it indicates that the graft has not survived and should be regrafted immediately.

[Loosen the band] Allow the bud of the scion to break the membrane automatically after the graft is successful. The grafted buds sprout slowly. At first, the first few new leaves are pink. After about 2 to 3 weeks, the leaves begin to turn light green and unfold. When the young leaves turn completely green and flatten, the plastic film can be loosened to avoid affecting the growth of new shoots. However, the healed grafting site cannot be untied immediately to protect the scion from damage.

[Bud Removal] For grafted seedlings , the buds on the rootstock should be removed at any time so that nutrients can be concentrated on the new shoots that have been grafted and survived.

[Other management] Timely tillage, weeding and reasonable watering, emphasizing the frequent application of thin fertilizers and heavy nitrogen fertilizers. New shoots are often damaged by herbivorous insects such as leaf beetles and geometrid moths, such as the larvae of alder leaf beetles and Pistacia geometrid moths. When the damage is small, artificial killing can be used. When the damaged area is large, chemical control is adopted: 800 times diluted 80% DDT or 50% carbofuran , 800-1,000 times diluted 25% phosmet emulsifiable concentrate , 1,000 times diluted 80% chlordimeform , etc. are commonly used.

Seed propagation

Seed collection: The capsule bursts easily when ripe, and the seeds fly away with the cotton wool, so they must be harvested before the fruit cracks.

Sowing: Plant in the soil around March in spring.