What are the latest propagation methods for Cornus officinalis?

Cornus officinalis is a positive tree species of the warm temperate zone, mainly produced in China's Shanxi, Shaanxi, Gansu, Shandong, Jiangsu, Zhejiang, Anhui, Jiangxi, Henan, Hunan and other provinces. Propagation methods include layering, cuttings, grafting and seed propagation. Let's take a look together below!

Layering propagation

After harvesting the fruit in autumn or before the ground thaws and the buds sprout, bend two- or three-year-old branches near the ground down to the ground, cut the branch near the ground to 1/3 into the xylem and bury it in soil already applied with rotted hot stable manure, cover with 15 cm of sandy loam, and leave the tip of the branch exposed above the ground. Water frequently. In the second winter or third spring of layering, cut the rooted layer from the part connected to the mother plant, and plant the rooted seedling elsewhere for final planting.

Cutting propagation

Usually in mid- to late May, cut branches from superior mother plants, cut the lignified branches into cuttings 15-20 cm long, keep 2-4 leaves on the upper part of the branch, insert them into a seedbed made of mixed humus soil and fine sand, with row spacing of 20 cm×8 cm and depth of 12-16 cm, cover with 12-16 cm of soil, and firm it. Water thoroughly, cover with agricultural film, maintain air temperature at 26-30°C and relative humidity at 60%-80%, set up a shade shed above with 25% light transmittance, and adjust light transmittance to 10% in mid-June to avoid strong light exposure. Remove the shade shed before overwintering and water thoroughly. The next year, loosen the soil and pull weeds appropriately, strengthen water and fertilizer management, and lift the seedlings for final planting in late autumn and early winter or early spring of the following year.

Grafting propagation

Seedling propagation of Cornus officinalis is difficult; the seedlings produced can only bear fruit more than 10 years after final planting, while grafted seedlings can bloom and bear fruit in 2-3 years. Using grafted seedlings can make Cornus officinalis bear fruit early and benefit early.

1. Rootstock selection: The rootstock should preferably use seedlings grown from its own improved seeds.

2. Scion selection: Select scions from high-yielding, robustly growing, pest- and disease-free superior mother trees. When collecting scions, collect well-developed, plump-budded one-year-old branches from the outer canopy.

3. Grafting time: The rootstock begins to sprout in early spring. When the scion buds just begin to sprout (around mid- to late March), use bark grafting; from mid-July to mid-August, when the rootstock bark is easy to peel and the scion buds are plump, perform bud grafting.

4. Grafting methods

① Bark grafting: First choose a smooth, flat part of the bark close to the ground at 5-10 cm, cut off the upper tip of the rootstock, smooth the cut, make a cut from top to bottom on the windward side with a grafting knife, about 3 cm long, reaching the xylem, then use the knife to pry open a crack in the bark at the interface, then cut the scion into 15 cm lengths. On the lower side of the back of the main bud, cut a slanted surface 3-5 cm long, passing through the pith, and lightly scrape 2 cuts on both sides of the cut surface to expose the cambium. Put the prepared scion in the mouth to keep it moist for later use. Next, place the slanted surface of the scion facing inward, point the tip toward the cut slit, press the rootstock cut tightly with the hand and slowly insert the scion, then lightly tap the interface with the grafting knife to make it firm, with the cut surface slightly exposed at the interface as appropriate, and finally tie the interface well with plastic film. After grafting, promptly remove the young shoots sprouting on the rootstock. When the scion seedling grows to a height of 50 cm, use a small knife to cut open the bound plastic film.

② Bud grafting method: First choose a mature, robust scion and take a bud 2 cm long and 1.5 cm wide from it. Cut off the top tip of the rootstock, and at a smooth part 5-10 cm from the ground, use a knife to cut out bark the same size as the bud piece. Insert the bud piece to be grafted into the bark-removed part of the rootstock, then bind tightly with plastic film, but expose the grafted bud. After 7-10 days of grafting, once the interface has healed, the binding can be untied, and the main trunk can be cut off 5 cm above the bud. After grafting, promptly wipe off the sprouts on the rootstock to promote seedling growth.

Seed propagation

1. Nursery site selection: The nursery site should be chosen in a place with fertile and deep soil, relatively flat terrain, loose soil, sheltered from wind and facing the sun, and with irrigation conditions, to ensure water can be supplied at any time. Before sowing, the nursery site must be deeply plowed and finely harrowed, leveled and refined, ensuring it is loose, fine, flat, free of tree roots, and free of stones and tiles. The plowing depth should be more than 20 cm. Importantly, apply well-rotted farmyard manure in combination with deep plowing.

2. Seed preparation

① Seed collection: Select superior mother trees that grow robustly, are in the full fruiting period, and have no alternate bearing. In September-October, pick fully mature, large and plump, pest- and disease-free, undamaged, dark red fruits. Remove the flesh from the picked fruits.

② Seed treatment: The quality of seed treatment directly affects the seedling emergence rate and is very critical. First put the seeds into 5% alkaline water, rub with hands for 5 minutes, then add boiling water to scald them, stirring while pouring boiling water until the boiling water submerges the seeds. Wait until the water is slightly cool, then rub with hands for 5 minutes, soak in cold water for 24 h, then remove the seeds and spread them on a cement floor to sun-dry for 8 h. Repeat this for at least 3 days, and when 90% of the seed shells have cracks, mix wet sand with the seeds at a ratio of 4:1 and store them in sand. Spray water frequently to maintain moisture and check frequently to prevent the seeds from becoming moldy. In the second spring, open the pit and take the seeds for sowing. This treatment method is suitable for spring sowing. If autumn sowing is chosen, simply soak the seeds in warm water not lower than 70°C for 3 days and then sow (note that after the water has cooled thoroughly, replace it promptly with hot water), and after sowing cover with film to promote germination.

3. Sowing method: Spring sowing for seedling cultivation is carried out around the Spring Equinox. Dig out the seeds stored in sand from the previous autumn and sow them. Before sowing, open shallow furrows about 5 cm deep on the seedbed at a row spacing of 30 cm, evenly scatter the seeds into the furrows, cover with 3-4 cm of soil, keep the soil moist, and seedlings can emerge in 40-50 days. The seeding rate is 90-150 kg/hectare.