cultivation techniques
breeding method
Rooting propagation and cutting propagation are the main methods of Dahlia propagation, and Dahlia can also be cultivated through seed propagation.
Split root propagation
In the spring of March-April, take out the stored root tubers, cut each root together with the buds attached to the root neck (the incision is coated with plant ash for anticorrosion), and plant them separately. Because dahlias only have buds on the root neck, there must be buds on each root neck. A root without a root neck or a bud point on the root neck does not germinate and cannot be planted. If the germination point on the root neck is not obvious or difficult to identify, it can be accelerated in early spring, and the root clumps can be arranged closely in the hotbed, then covered with soil, watered and given a certain temperature, and then divided into plants after germination, and each plant has at least one bud. The propagation by ramets is simple and easy, with high survival rate and strong plants, but the propagation coefficient is not as high as that by cutting.
cutting
1. Soil preparation: select a field with deep ploughing layer, loose and fertile land, flat terrain and good drainage, apply 125 kg of calcium superphosphate as base fertilizer per mu before deep ploughing, add 0.5 kg of 50% subsoil to disinfect the soil until the soil is deeply ploughed to about 15 cm, and then harrow it to make high ridges.
2. Cutting method: from June to August, the lateral buds grow to 1.5 ~ 20cm, and cutting and sowing are combined. Cutting requires three buds, leaving two buds on the upper part, cutting the third bud to the leaf base to remove leaves, inserting it into the soil to water the second bud, and shading the stand with 50% shading net. Water it once in the morning and evening on sunny days, and water it continuously for half a month. The soil moisture is kept at 90%. Rooting after three weeks, the survival rate is high, and it can bloom in the autumn of that year.
3. Post-cutting management: After the cuttings survive, combined with intertillage weeding, topdressing with saturated leaching solution of compound fertilizer once before and after flowering, and topdressing with 400 ml of mother liquor after every 65,438+0 back spraying (about 65,438+02.5 kg). Dahlia should not be cultivated in deep ploughing and intertillage after taking root, so as not to hurt the root tuber and prevent grass damage. Because the meat of plants is soft, it is necessary to erect supports to prevent the stems and leaves from breaking. Topping when the height of floret seedling 15 cm will make the plant short and strong and blossom more. Flowers will be picked in time after withering to prolong the flowering period.
Seed propagation
Seed propagation plays an important role in Dahlia cultivation and is suitable for varieties that are easy to bear fruit. Generally, the seeds harvested in autumn should be sown in February-March of the following year at 15~20℃ during the day and not lower than 12℃ at night. [2] Seedlings propagated by seeds have strong vitality, healthy growth and strong adaptability, and a large number of plants can be obtained in a short time, but flowering and fruiting are slow. The flowering period is late, so it can't keep the excellent characteristics of the female parent and degenerate.
1, preparation before broadcasting
(1) Seeding container
Select a seedling tray with a length of 50 cm, a width of 20 cm and a height of 5 cm, rinse it with clean water first, and then disinfect it with 0.2% chlorine-free nitrobenzene.
(2) sowing the substrate
Choose soil with fine and uniform texture, no stones, no pollution, rich nutrition and no pests and diseases. Soil with good drainage and low salt content is suitable. The selected sowing substrates are garden soil and peat. Generally, it is made of garden soil, humus soil and river sand in the ratio of 2: 2: 1, and disinfected with 2% pentachloronitrobenzene or high temperature.
2. Sowing method
(1) sowing time
Clean the sterilized seedling tray with clean water before sowing. Sow immediately after seepage. Sow the hotbed in the middle and late March, and sow the flower bed varieties in the open field in the late April, and the seeds are scattered on the soil surface. After sowing, the big seeds are covered with wet fine soil, the thickness of which is three times the diameter of the seeds. Covering the agricultural film with bamboo poles after sowing, leaving gaps for ventilation, is conducive to raising soil temperature, reducing moisture, maintaining soil moisture and reducing soil hardening, thus maintaining the temperature and humidity required for seed germination. After sowing, it is placed at 20~25℃. After sowing for about 7 days, the seeds can germinate. Always keep the soil moist. When the seedlings grow to 4~5 cm, water them, place them in the shade for 3~4 days, and then move them to strong light. Pay attention to water in time to keep the soil moisture.
(2) Post-broadcast management
Water according to soil moisture. Keep the soil dry and moist. When the soil surface is slightly dry, keep it moist by soaking. The suitable temperature for seed germination is 19~2 1℃. Regular ventilation after sowing is beneficial to seed germination. The seed germination of Dahlia needs proper shading. After the seedlings emerge neatly, gradually remove the film and move the seedlings to the sunny place. Rotating boxes at 180 every 2-3 days is beneficial to the straight growth of seedlings.