The 1000-grain weight of peony seeds is about150g-180g. Therefore, the propagation coefficient of sowing propagation is large, and a large number of seedlings can be obtained in a short time. According to this feature, peony sowing and propagation are mostly used to produce medicinal peony and cultivate rootstocks for grafting. Single-petaled peony varieties have strong seed setting, full seeds, high germination rate, wide adaptability, strong growth potential and small variability, among which the single-petaled variety "Feng Dan" is the most representative. Therefore, when producing medicinal peony and cultivating rootstocks for grafting, there are many seeds with single petals, especially "Feng Dan". The stamens or pistils of semi-double-petal or double-petal peony varieties are often petal-shaped or degenerated, with few or no seeds, withered seeds, low germination rate and great variability. Therefore, semi-double petals or double petals are generally used to breed new varieties. The seeds of single-petal varieties, semi-double-petal varieties and double-petal varieties will not bloom until 3-5 years after sowing, but plants over 5 years old will bear more fruits and full seeds.

1, seed harvesting

The fruit of peony is a capsule. Generally, a fruit has 3-5 pods, and each pod contains 6- 10 seeds.

Peony seeds should be harvested in batches at the right time, not too early or too late. Premature seeds are immature, tender and rich in water, and easy to rot or shrink; Too late, the seeds turn black, hard and thick, and the maturity of the seeds has a great influence on the germination rate. Generally, when the outer shell of the follicle is brown or brown, the seeds should be harvested in milky yellow or reddish brown. In Heze and Luoyang, seeds are usually harvested from late July (high temperature in summer) to early August (beginning in autumn).

2, seed pre-sowing treatment

After the fruit is harvested, it should be spread in a cool and ventilated place until it matures in the later stage. Don't be exposed to the sun, otherwise the seeds will lose their germination ability once they are dry, and the places where the fruits are laid should not be too dry or too wet. If it is too dry, the juice in the shell will soon dry up, the seeds will not be fully mature, and even dehydration will cause the seeds to dry up; Too wet can cause fever or mildew. Turn it every 1-2 days to prevent it from getting angry and getting moldy. After 10- 15 days, the pods gradually turn brown or black, most of them crack by themselves, and a few of them can be peeled off manually, then the pods are removed and the seeds are picked out.

In order to eliminate the influence of withered seeds on germination rate, the picked seeds can be soaked in clean water for 65438 0-2 hours, and then the impurities floating on the water surface and withered seeds can be removed, and the full seeds submerged in water can be used for sowing.

Water permeability and air permeability of peony seed coat are important factors affecting seed germination. Before sowing, seeds can be soaked in 50℃ warm water for 24-48 hours, or soaked in 95% alcohol for 30 minutes, or soaked in concentrated sulfuric acid for 2-3 minutes, which can soften the seed coat and promote germination. But the seeds must be washed with water after soaking.

Peony seeds have the characteristics of hypocotyl dormancy. In autumn, only the hypocotyl grows downward, and the radicle breaks through the seed coat to form a young root, which does not germinate until the next spring. Treating peony seeds directly with 100-300mg/L gibberellin (GA-3) for 72 hours can promote the growth of radicle, but it has no effect on relieving the dormancy of epicotyl (embryo). Only when the radicle length is more than 3cm, when treated with 100mg/LGA3 for 24 hours, the dormancy of epicotyl can be effectively broken, and the seeds can be transformed from rooting growth to germination growth.

3, sowing time and method

The sowing time of peony is generally from late August (summer) to early September (white dew), which will affect the germination rate of seeds too early or too late. This dependence of peony seed germination on seasons may be a reflection of its optimum temperature. Some peony seeds are in the seeds.

The optimum temperature for germination is 65438 05℃, which is very close to the temperature of peony seeds exposed from September to June. In addition, the in vitro embryos of "Feng Dan" seeds inoculated in sterile medium have no growth reaction at 5℃, but grow slowly at 65438 05℃ and rapidly at 65438 05℃, but tend to grow callus at 20℃. If it is impossible to sow immediately for other reasons, the seeds should be mixed with fine sand and piled indoors or put into a soil basin to store sand. During sand storage, it should be kept moist, and the sand storage time should not exceed 65,438+05-20 days. Seeds must be sown when they take root. Sowing should be done with sandy loam and sufficient fertilizer should be applied. Generally, decomposed cake fertilizer 100-200 kg is applied every 666.7m2, carbofuran or phoxim 15-2-5kg is applied every 666.7m2, and thiram or duofu is 2-5kg.

If the soil moisture is moderate, it can be deeply ploughed and leveled; If the ground is dry without rain, it should be watered first, and then ploughed and leveled when the soil humidity is suitable.

Peony planting generally adopts small high border, with border height of 8- 10 cm, border width of 50-60 cm and border spacing of 30-50-60cm.

Ditch depth 15-20 cm, and sowing methods vary with the amount of seeds. When the seeds are sufficient, they can be sown, the spacing between plants should be more than 3cm, and it should not be too dense, and sowing is about 50kg every 666.7m2; When the amount of seeds is small, you can sow, generally the row spacing is 6- 10cm, the plant spacing is 5-8 cm, the outermost part is generally away from the border 10cm, and the amount of seeds used for sowing is generally 25-35 kg per 666.7 m2. If the purpose is to cultivate new varieties, it should be planted as needed, with the row spacing of 20-30cm and the plant spacing/kloc.

After sowing, cover the border with 2-3 cm thick fine soil with moderate water content, and then cover it with plastic film to prevent drought, preserve moisture and raise ground temperature.

4. Management after sowing

Peony generally begins to take root 35-40 days after sowing, and begins to sprout around the vernal equinox in the following year. At this time, the ground temperature is about 4-5℃, and the ground grows around Qingming. At the beginning of May, the seedling height is 3-5 cm, and three leaflets are planted to enter the seedling stage.

In winter, when the ground begins to freeze around (65438+late February), the plastic film of the seedbed should be covered with a layer of straw or corn stalk for wintering protection. If the ground is dry, water can be poured in the border ditch once as "winter water" to avoid flooding the border surface and causing soil hardening.

During the period from late February (rain) to mid-March (vernal equinox) of the following year, the winter mulch should be removed immediately after the ground is thawed to facilitate the germination and excavation of seeds. If there is too little rain and snow in winter, you can water the seeds again before germination.

It is vulnerable to underground pests at seedling stage, and it can be lured and killed by spraying or mixing poison bait with methyl isofenphos, carbofuran, 1605 and phoxim. When sprayed, it can be mixed with methyl chloropicrin and can prevent seedling damping-off.

If the drought persists in late May and early June, you can water it once or twice. After each watering or rain, soil loosening, weeding and moisturizing should be carried out in time.

Seedling leaf spot is easy to appear after mid-May. At this time, it can be controlled by spraying Lvheng 1, carbendazim and carbendazim, and can be mixed with foliar fertilizer to achieve the purpose of preventing diseases and strengthening seedlings. Spray once every 15-20 days, and spray continuously until September.

If it is used to produce medicinal peony, the seedlings can be transplanted after two years of growth 1-2, the row spacing is 40×60cm, each hole 1-2 plants, and each plant is 666.7m2.

If rootstocks are cultivated for grafting, the seedlings can be continuously cultivated in situ for 2-3 years, preferably 3 years, and more than 85% of the seedlings can be used as rootstocks; You can also replant 1 year-old seedlings with a row spacing of 20×50cm and cultivate them for 2-3 years before grafting. Compared with seedlings grown in the same place for 2-3 years, the root system is larger and the stored nutrients are richer, which can significantly improve the grafting survival rate and enhance the growth potential of grafted seedlings.

If new varieties are bred, the spacing between plants should be appropriately increased when sowing, and they can grow continuously for 3-5 years in situ, so that they can blossom as soon as possible, which is convenient for selection and shortens the whole breeding cycle.

Seedling transplanting time should be from early September (Bailu) to late September (autumnal equinox). When raising seedlings, dig a ditch with a depth of 40-60 cm from one end of the border, bury it vertically with a shovel or a hairpin, turn the soil and seedlings into the ditch and pick out the seedlings.

Dig holes according to the distance between plants and the size of peony seedlings. When planting, put the seedlings vertically into the holes, hold the seedlings with one hand and fill the holes with the other. When the soil fills two-thirds of the holes, gently lift the seedlings up by hand to make the roots straight and the terminal buds 1-2cm above the ground. Then tamp the soil around the seedlings with wooden sticks or hands, and fill the pit while tamping. In order to prevent drought and keep warm in winter, the bud is sealed into a small mound with fine soil, which is generally about 5 cm higher than the bud. Before and after the first ten days of March of the following year (when the land is thawed), the soil above the peony should be gradually removed to facilitate the growth of buds.