Key Techniques for Grafting Ginkgo onto Seedling Rootstocks
Seedling rootstock grafting is a new technique developed in recent years. Compared with ordinary grafting methods, it shortens the seedling-raising time by one year, has a high survival rate, produces good-quality seedlings, and costs less. With such a good new technique, isn't it time to learn it quickly?
The seeds are first pre-germinated indoors. The germinated seeds are raised in nutrient pots, with 1 seed placed in the soil of each pot. The seeds should be placed on their side so that the radicle grows downward and the hypocotyl grows upward without bending, making grafting easy. Cover with an appropriate amount of nutrient soil, then place the nutrient pots for raising seedlings in a greenhouse. Before the seedlings emerge, keep the temperature at 25-30°C; after the seedlings emerge, keep the temperature at 20-25°C, increase light, and promote thickening growth of roots and stems. When the embryo bud grows to 3 cm and the first pair of true leaves is about to unfold, it can be used for seedling rootstock grafting.
In mid-March, before the branches and buds begin to sprout, collect 1-2-year-old branches with plump young buds and a thickness of 0.3-0.4 cm from superior, robust, mature mother trees that have already fruited. Wrap them in plastic film and store them moist at a low temperature of 0-2°C in a cold storage room or refrigerator to keep them fresh. When the young buds of the rootstock seeds are about to unfold true leaves, lift the seedlings for grafting.
Cut off the rootstock sprout about 3 cm above the cotyledon petiole, and make a 2 cm cut along the cotyledon petiole and the center of the embryonic stem. Sharpen the lower part of the scion into a wedge shape, with both cut surfaces 1.5 cm long, and keep 1-2 buds on the upper part. Insert the prepared scion into the cut, then bind it firmly with plastic tape and keep it in the greenhouse. Because the rootstock is young and tender and the scion is short and small, healing is relatively slow, so spray warm water once every morning and evening. Keep the greenhouse temperature at 20-25°C and the relative humidity at 80%. After about 25-30 days, the scion and seedling rootstock heal well, and the scion begins to sprout. After survival, loosen the binding in time. After the leaves unfold, 15-20 days later, cut off the kraft paper or agricultural film, and transplant into the nursery at a row spacing of 40 cm × 20 cm, with 50%-60% shading, which is removed in late August.
Grafted seedlings can bear fruit 3-4 years after planting, and they maintain the excellent characteristics of the scion, with superior traits such as fast growth, high yield, and ease of cultivation.
The above is the new grafting technique summarized for you. We hope it can help you. Huinong Academy has even more related agricultural technical knowledge, so keep following Huinong Academy to answer your questions during the planting process.
Seedling Rootstock Grafting Propagation of Ginkgo
This method is a new technique developed in recent years. Compared with ordinary grafting methods, it shortens the seedling-raising time by one year, has a high survival rate, produces good-quality seedlings, and costs less.
The seeds are first pre-germinated indoors. The germinated seeds are raised in nutrient pots, with 1 seed placed in the soil of each pot. The seeds should be placed on their side so that the radicle grows downward and the hypocotyl grows upward without bending, making grafting easy. Cover with an appropriate amount of nutrient soil, then place the nutrient pots for raising seedlings in a greenhouse. Before the seedlings emerge, keep the temperature at 25—30°C; after the seedlings emerge, keep the temperature at 20-25°C, increase light, and promote thickening growth of roots and stems. When the embryo bud grows to 3 cm and the first pair of true leaves is about to unfold, it can be used for seedling rootstock grafting.
In mid-March, before the branches and buds begin to sprout, collect 1—2-year-old branches with plump young buds and a thickness of 0.3—0.4 cm from superior, robust, mature mother trees that have already fruited. Wrap them in plastic film and store them moist at a low temperature of 0-2°C in a cold storage room or refrigerator to keep them fresh. When the young buds of the rootstock seeds are about to unfold true leaves, lift the seedlings for grafting.
Cut off the rootstock sprout about 3 cm above the cotyledon petiole, and make a 2 cm cut along the cotyledon petiole and the center of the embryonic stem. Sharpen the lower part of the scion into a wedge shape, with both cut surfaces 1.5 cm long, and keep 1-2 buds on the upper part. Insert the prepared scion into the cut, then bind it firmly with plastic tape and keep it in the greenhouse. Because the rootstock is young and tender and the scion is short and small, healing is relatively slow, so spray warm water once every morning and evening. Keep the greenhouse temperature at 20-25°C and the relative humidity at 80%. After about 25—30 days, the scion and seedling rootstock heal well, and the scion begins to sprout. After survival, loosen the binding in time. After the leaves unfold, 15-20 days later, cut off the kraft paper or agricultural film, and transplant into the nursery at a row spacing of 40 cm × 20 cm, with 50%-60% shading, which is removed in late August.
Grafted seedlings can bear fruit 3—4 years after planting, and they maintain the excellent characteristics of the scion, with superior traits such as fast growth, high yield, and ease of cultivation.
A Brief Introduction to Ginkgo Tree Care Methods
Care of Ginkgo Trees Ginkgo
Ginkgo, also known as white fruit, is a large deciduous tree in the Ginkgo family.
Its tree body is tall, the trunk is straight, and its posture is majestic. The leaves are fan-shaped, and after autumn they turn entirely golden, making it extremely spectacular.
Ginkgo is an excellent tree species for landscaping, ornamental use, and street planting. Its fruit and leaves have important medicinal value, and the fruit is a top-grade nutritional tonic.
Common cultivated ornamental varieties of ginkgo include yellow-leaf ginkgo, whose leaves are bright yellow; tower ginkgo, whose branches rise into a narrow tower shape or columnar shape; split-leaf ginkgo, whose leaves are larger with deep notches or splitting; weeping ginkgo, whose branchlets droop; and variegated-leaf ginkgo, whose leaves have yellow markings.
(1) Growth characteristics: Ginkgo grows slowly, commonly known as the "gong sun tree," and has male and female plants. Its main root is deep, and it has strong adaptability. It likes light and a warm, humid climate, and fears waterlogging. It is suitable for growing within an annual average temperature range of 8-20°C. Sandy loam soil and beach alluvial sandy soil are most suitable, and it can also grow in other soils.
(2) Propagation methods: Seed sowing for seedling raising is mainly used, and cutting or division grafting propagation can also be used. Raising ginkgo seedlings by sowing is difficult, with a low survival rate. Measures such as stratification after-ripening and pre-germination sowing should be used for the seeds.
① Two-stage seedling raising technique with plastic film mulching
Seed selection: Choose plump, fresh seeds whose embryos can germinate normally.
Storage: Mix and pile the seeds with 3 times their volume of sand indoors, keeping the sand moist, with the degree that it forms a ball when squeezed by hand without falling apart, to prevent drying out.
Land preparation: Choose a plot with flat terrain, loose soil, and drainage and irrigation conditions. Sow 5 kg of seeds per 7 sq m, apply 100 kg of high-quality farmyard manure as base fertilizer, and add 0.5 kg of nitrogen-phosphorus-potassium compound fertilizer. Deeply plow the soil before winter. Before spring, as early as possible, form ridges running east-west at 10 m × 0.7 m, with a ridge height of 6 cun, ready for sowing.
Sowing: The suitable sowing period is late February to early March. Before sowing, open a ditch 2 cun deep and 7 cun wide in the middle of the prepared ridge, water the bottom with a 0.1% ferrous sulfate solution to increase bottom moisture and disinfect, then evenly scatter the seeds together with the sand into the ditch, and scatter poisoned bait for trapping and killing underground pests in the seed row (for every 7 sq m, use 0.5 kg of wheat bran fried yellow, mixed with 20 g of trichlorfon and 20 g of sesame oil to make the bait). Cover the seeds with soil, with a covering thickness not exceeding 3 times the thickness of the seeds. Then choose 60 cm wide plastic film to cover, compact both sides to preserve moisture and increase soil temperature.
Film removal: In mid-to-late April, once 50% of the seedlings have emerged, remove the plastic film in time to avoid high temperatures scorching the young seedlings.
Shading: Newly emerged seedlings are not tolerant of high temperatures, so shade netting can be used for sun protection.
Field management: Water and weed as needed, and promptly prevent and control pests and diseases. After the summer solstice, spread 3-4 cm thick wheat straw between the rows of ginkgo seedlings, which can preserve moisture, prevent weeds, and lower surface temperature.
Separate planting: Plant separately in the second year. Transplant in late February to early March, using wide and narrow rows (wide row 50 cm, narrow row 20 cm) with a plant spacing of about 15 cm. In addition, pay attention to drought prevention and waterlogging prevention, and promptly weed, apply topdressing, and prevent and control pests and diseases.
② Cutting propagation: From mid-June to mid-July, collect young branches from robust, superior mother trees 30-50 years old for cuttings.
Take semi-lignified branches from the middle and upper part of the crown, cut them into 10 cm long cuttings, remove the lower leaves, keep 2-3 leaves, sharpen the base into a slanted surface and insert it into the seedbed, leaving 1-2 buds above the ground. Cover with plastic film, water 4-5 times a day, maintain 24-25°C and relative humidity above 90%, and roots can form in 40-45 days. If the base of the cuttings is quickly dipped in 1000*10 to the negative 6th power indolebutyric acid (IBA) before cutting, then the rooting rate can reach more than 95% in just over 20 days.
③ Layering and division: In early spring, on the vegetative branches of superior 2-3-year-old mother plants, make a ring-shaped bark girdle 0.5 cm wide at 30-40 cm from the tip, and wrap the area 10 cm above and below the cut with wet moss or wet loess, then wrap the outside with a layer of plastic film, tie both ends tightly with rope, and water in time. In autumn, 3-4 roots 2-3 cm long grow from the wound, and they can be cut off from the lower end of the plastic film and transplanted into the nursery. They bear fruit 8-10 years earlier than seedling plants. Trees 20-30 years old are prone to producing suckers. In early spring, loosen the soil around the roots and apply barnyard manure to promote the mass production of suckers. In mid-May, thin the suckers, keep the strong seedlings, separate them from the mother tree the following spring, and transplant them into the nursery. They can bear fruit 10 years earlier than seedling plants.
④ Grafting: Grafting can use cleft grafting, bark grafting, "T"-shaped budding, seedling rootstock grafting, and so on.
Here are some explanations on seedling rootstock grafting. Use seedlings propagated from seeds as rootstocks. The grafting operation should be light and quick to prevent water loss and damage to the seedlings. When sowing, the seeds must be placed on their side so that the radicle grows downward and the hypocotyl grows upward without bending. After the seedlings emerge, water should be controlled to promote thickening growth. When the embryo bud is 2.5-3 cm high and the first pair of true leaves unfolds, the seedlings can be lifted for grafting. Cut off the seedling about 3 cm above the cotyledon petiole, hold the cotyledon petiole with the hand, and cut downward along the center of the embryonic stem into a 2 cm long cut. The scion should have 1-2 buds, and its lower end should be sharpened into a wedge shape, with both side cut surfaces 1.5 cm long. Insert the scion into the cut, then bind it tightly with a plastic film bag. Move the grafted seedlings to a seedbed or plastic bag to heal, using vermiculite as the substrate. Then cover with plastic film to keep warm and moist. The moisture content of the vermiculite is 40%-50%, and the relative humidity on the bed is about 90%. The suitable temperature for wound healing is 20-25°C. Pay attention to frequent watering and ventilation. After about 20 days, the scion begins to sprout. After the leaves unfold, it can be transplanted to the nursery, with strengthened loosening of the soil, weeding, and prevention and control of pests and diseases.
(3) Cultivation and management
① Seedling stage: Promptly carry out intertillage and weeding, prevent and control pests and diseases, and prevent drought and drain waterlogging, so that the seedlings grow in moist, loose soil. During the seedling stage, topdressing is generally applied 3 times. The first time is in early June, applying a small amount of diluted decomposed human manure and urine together with irrigation. The second time is in early July, and the third time is in early August, gradually increasing the fertilization level a little each time, and appropriately adding phosphorus and potassium fertilizer or applying some plant ash.
② Planting and management: Ginkgo has strong rooting ability. From after leaf fall to before sprouting, small seedlings can be transplanted bare-rooted, while large seedlings should be transplanted with native soil. They can be planted in the ground or in pots. During the seedling stage, branches grow quickly, so pruning must be paid attention to. Repot once every spring, and strengthen fertilizer and water management after planting to promote growth. Ginkgo is a dioecious wind-pollinated plant, so male plants should be planted at a ratio of 1/2, and attention should be paid to the wind direction when planting, so as to ensure normal fruiting.
(4) Pest and disease control
① Pests: The main pest of ginkgo is the ginkgo tussock moth, also known as the white fruit worm. Its larvae feed on leaves. As the larval age increases, leaf feeding becomes severe. Biological control with Trichogramma, light trapping, and manual capture can be used. For chemical control, spray 500 times trichlorfon or 500 times 50% bisultap.
The small leaf roller moth mostly harms old trees, causing weak tree vigor, thin and weak branches, leaf fall, fruit drop, and failure to sprout the next year. It then turns to feeding on the leaf mesophyll, and even climbs onto the trunk to bore into and eat the bark. From late March to early April, using 800 times 80% dichlorvos mixed application has an effect of 100%. In mid-June, most larvae bore into the trunk. Use a mixture of undiluted dichlorvos, o-dichlorobenzene, and diesel oil in a ratio of 4:5:10 to prepare an oil mist agent and spray the trunk, with very good results.
② Diseases: White fruit mold rot: This often occurs during storage. After infection, there is a layer of dark green mold on the outer seed coat. After cutting open, the seed kernel is mushy and has a distiller's grains smell, seriously affecting the commercial value and germination rate of white fruit. For control, pay attention to harvesting seeds after they are fully mature, fully sun-dry them before stratified storage, soak them in 0.5% potassium permanganate solution for 30 minutes, then rinse with clean water and dry them. For wet sand, spray and disinfect with 40% formaldehyde diluted 10 times. The storage temperature should be 0-4°C, and attention should be paid to appropriate ventilation.
Ginkgo stem rot: It occurs more seriously in areas with high temperatures, intense heat, and more rain. In severe cases, the seedling death rate reaches more than 90%. It mostly occurs on 1-2-year-old seedlings. After infection, the stem base turns brown, and the bark gradually shrinks. The leaves droop and lose their normal green color. The inner tissue of the stem base rots into a spongy or powdery state, grayish white, with many small black seedling sclerotia, and spreads to the xylem, pith, and roots. Then the root bark falls off and the whole plant dies. In hot seasons, the pathogen enters weak seedlings from the soil through scorching injury, waterlogging, and mechanical damage. For control, strong seedlings should be cultivated, shading should be provided in hot seasons, water should be drained when there is too much rain, watering should be done during drought and high temperature, straw should be spread between seedling rows to preserve warmth and moisture, the field should be kept clean, and diseased plants should be pulled out in time. During the disease period, spraying with 1% sulfurous acid solution has a certain effect.