Breeding techniques of Angelica sinensis

Angelica sinensis is propagated with seeds, generally using the method of raising seedlings and transplanting, or direct seeding.

1. Seedling raising and transplanting

(1) selected seeds: the yield of Angelica sinensis seeds is about 14.6 kg higher than that of unselected seeds per mu. The main method of selection is ear selection. During the harvest of Angelica sinensis, when the seed epidermis is blue or pink and the scape is drooping, the ears with the characteristics of this variety, good growth, no diseases and insect pests and high maturity are selected, cut off together with the scape, dried in a ventilated and dry place, threshed and stored. As the seeds of Angelica sinensis are not consistent in maturity, seed harvesting must be carried out in batches, ripe one branch, cut one branch, and remove mildew, hybrid, blighted seeds and seeds damaged by diseases and insect pests, select full and full seeds as seeds, and avoid harvesting the whole plant. In order to ensure the seed quality, the germination test should be done before sowing.

(2) pre-sowing treatment: in order to make the seeds germinate quickly and emerge evenly after sowing, soaking seeds is often carried out before sowing, so as to make the seed coat absorb water and soften in a short time, increase permeability and promote seed germination. Angelica seeds were soaked in 25: 30 ℃ warm water for 24 hours, then dried and mixed with plant ash at 1:10.

(3) sowing time: the suitable sowing time should be determined according to the local altitude, air temperature and other conditions, not too early or too late. Early, easy to occur early bolting; late, the seedlings are too small, poor stress resistance, low survival rate. It is suitable to sow seeds in high altitude areas with low temperature in early and middle June, and from mid-July to early August in low altitude areas with higher temperature. No matter the time of sowing, the seedling age should not exceed 110 days, and the weight of 100 seedlings should not exceed 40 grams.

(4) sowing method: seedling sowing is generally used for sowing or strip sowing. Spread the seeds evenly on the seedbed, cover with a layer of fine fertilizer about 0.5 cm thick and 1.0 cm thick, and then cover with hay about 3 cm thick to preserve moisture. Where there is little rainfall, sowing had better be carried out before the rain, so as to make the emergence of seedlings neat and healthy. Strip sowing should open a horizontal trench according to the row spacing of 20 cm, with a depth of 3 cm to 5 cm. When sowing, seeds should be evenly sowed in the furrow, covered with fine soil, and then covered with dry grass or shed for shade.

(5) sowing rate: the yield per unit area of Angelica sinensis is composed of the number of plants and the root weight per plant. The amount of sowing and whether the sowing is uniform or not will affect the growth and yield of future seeds. The sowing rate is too small, although the growth is fast, the root is large and heavy, it is easy to form large seedlings and forked seedlings, and it is easy to bolt early after planting. If the sowing rate is too large, it is easy to form small and weak seedlings, and the survival rate is low after planting, and the planting cost is increased. In production, seeding is about 4kg per mu and strip sowing is about 4kg per mu.

(6) Seedling stage management: in order to improve the seed germination rate and make the seedlings strong, the seedling bed must be kept moist and covered with grass to preserve soil moisture. Seedlings usually emerge 15-20 days after sowing. If the soil is moist and the temperature is suitable, seedlings can emerge in 7-8 days. The newly unearthed seedlings are easily killed by strong sunlight, so the cover grass should be shaken loose to cover the seedlings. One month later, when the seedlings grow to a height of 1-2 cm, part of the covered grass on the border will be removed. After uncovering the grass, set up a shed or shade with a black net, the height is about 60 cm, the shade degree is controlled in full light, and the shade is removed after the summer day.

The seedlings grow out of 3 true leaves, and when they are 3 cm high, they can loosen the soil for the first time and carry out inter-seedlings to remove weak and diseased seedlings and keep the distance between plants about 1 cm. Remove weeds in the field at any time.

In order to prevent the vigorous growth of seedlings and the formation of large seedlings, bolting early after transplanting is generally not suitable for topdressing at seedling stage. Only in the late stage of seedling growth, topdressing human feces and urine or appropriate amount of ammonium bicarbonate.

(7) Seedling storage: seedlings should not overwinter in open field. Because of their poor drought resistance and high bolting rate through vernalization in the field, seedlings should be dug up and stored before ground freezing. The time of seedling emergence should be when the temperature drops to about 5 ℃ and the aboveground leaves begin to turn yellow. The producing areas of Gansu are generally around Cold Dew. The producing area of Sichuan is before and after Frosts Descent. Seedlings should be raised in sunny days to prevent rotting roots caused by rain. When raising the seedlings, dig up the seedlings with a small shovel, pull them out, strive for the integrity of the root system, strictly forbid to damage the buds and roots, then shake off the soil, cut off the leaves to retain the petiole of 1 cm long, remove the disease, residue, injury and rotten seedlings, separate them according to large, medium and small, bundle them into a handful of every 100 plants, and hang them on the dry soil in a cool and dry place for 5 to 7 days, so that the bark of the fresh seedlings is slightly dry, and the roots begin to soften (water content 60cm 65%). The petiole can be stored after shrinking. Do not dry for too long, the seedlings lose too much water. There are two methods of storing seedlings: cellar and dry storage, the drought resistance of dry storage is the strongest, and the drought resistance of cellar is poor. If there are conditions, it is best to freeze below 0 ℃.

Dry storage is called heap hiding. In a smokeless shelter room, a square pit of 100 cm and 100 cm wide is built with dry adobe, and the bottom of the pit is covered with a layer of soil, and then the seedlings are placed one layer outward from the center, tail to the center, head to the outside, and the outermost circle of each layer, leaving a 6 cm wide gap between the head of the seedling and the pit wall, such a layer of seedling soil, the pit is filled with a layer of thick soil, and the top is shaped like a fish back. Can also not build a pit, a layer of storage on the ground, and finally covered with soil into the shape of steamed bread. If the number of seedlings is small, you can also use baskets for laminated storage.

Cellar should choose dry, cool, no rat hole, non-seepage place to dig the cellar, the size of the cellar depends on the number of seedlings, the shape can be rectangular or round. The bottom of the pit is first covered with a layer of dry and wet raw soil, about 3 cm thick, and then a layer of seedlings and a layer of soil are placed in turn, with a height of about 65-75 cm. Finally, the top soil is higher than the ground to prevent the accumulation of water from causing decay. The seedlings should be staggered from head to tail and arranged neatly.

(8) transplanting: in order to reduce bolting ratio, seedlings for planting must be strictly selected. generally, seedlings are required to have complete roots, no diseases and insect pests, less smooth and forked roots, 3-5 mm thick, too large seedlings are easy to bolting, and too small seedlings are too weak to grow poorly. Angelica sinensis is often planted in spring, and the time of transplanting is different due to different elevations, temperatures and other conditions. The temperature is unstable in spring, transplanting too early, easy to be frozen to death by late frost after emergence, transplanting too late, the seedling has sprouted, and the later development is poor, and it is easy to hurt the seedling, affecting the survival, which generally starts after the Qingming Festival and ends before Grain Rain.

In recent years, spring planting has been changed to winter planting in Minxian County, Gansu Province. after several years of experiments, high yield has been obtained, which is more than 10% higher than that of spring planting. That is, the seedlings raised in that year were transplanted in the field from Cold Dew to Frosts Descent, and the following autumn was harvested with Angelica sinensis planted in spring. The advantage of winter planting is that the roots are stable and strong, turn green early the next year, and reduce the loss of storage infection and mildew in winter.

Transplanting methods vary from place to place. In the producing area of Sichuan, the seedlings are dug and planted on the box, with a spacing of 30 cm and a row spacing of 36 cm, with 2-3 seedlings per litter and 10 000-15 000 seedlings per mu. When planting, the root should be stretched and should not be bent. After a little filling and compaction, apply stable fertilizer, about 750 kg per mu, and then cover the root head with fine soil to prevent frost damage. Hole planting or furrow planting was used in Minxian County, Gansu Province. Hole planting is on the whole land, according to the row spacing of 24 × 33 (cm 2), triangular staggered digging and planting seedlings, the depth of the nest is 18 cm 21 cm, the diameter of the nest is 12 cm 15 cm, each mu is about 6000 × 8000 nests, each nest is enlarged, medium and small seedlings, and generally requires a net seedling of 15 kilograms per mu. Place the seedlings vertically in the nest and cultivate the soil to cover them. The cover soil is higher than the ground, which is called "Ming Wo", which is mostly used in the loose soil layer and fine soil preparation; the seedlings planted along the slope, the root head outward, and the root tail flat into the nest are called "Yang Wo", which is mostly used in the sloping land, which is helpful to maintain soil moisture and prevent the root from showing the soil surface after rain. After transplanting, cover the soil with 2 cm and 3 cm, and compact it slightly. The trench planting is on the finished border surface, the furrow distance is 40 cm, the depth is 15 cm, the plant distance of 3 cm to 5 cm is placed in the ditch alternately, the rhizome is 2 cm below the border surface, and the soil cover 2 cm.

In order to make Angelica develop neatly, some spare seedlings should be planted on the ground or border at the same time of transplanting.

2. Live broadcast

In order to prevent early bolting of Angelica sinensis, cultivators have done a lot of research, transplanting seedlings in summer to direct seeding in autumn, and controlling the size of seedlings, which not only prevents early bolting, but also reduces the processes of raising, raising, storing and planting seedlings, saves labor and reforms cultivation techniques. According to the experimental results of different sowing dates made by Northwest Botanical Research Institute in 1975, autumn sowing can effectively prevent early bolting. But the time of autumn sowing must be controlled, be sure to sow before and after the Beginning of Autumn, too early, can not achieve the purpose of preventing bolting; too late, the seedling resistance is poor. In short, the seedlings should be guaranteed to have a growth period of about 70 days, with 4 true leaves and a root diameter of about 0.2 cm in order to survive the winter safely. The areas with high altitude and low temperature are sown in early August, while those with low altitude and high temperature can be postponed to mid-August to early September.

As there is no problem of early bolting in direct seeding cultivation, it is appropriate to choose the old and full gunpowder seed as the seed, which has sufficient nutrition, strong vitality, fast seedling emergence and exuberant growth. In addition, the single root weight of direct seeding was slightly lower than that of seedling transplanting, and the production generally depended on increasing population density to increase yield. At the same time, because of its short growth cycle, in order to obtain high yield, in addition to applying sufficient base fertilizer, topdressing should be applied in time, more nitrogen fertilizer should be applied at seedling stage, and phosphorus and potassium fertilizer should be applied early after seedling.

The direct seeding site should choose the land with sunny, gentle slope and low elevation, which requires deep soil layer, fertile soil, loose soil and rich in organic matter. There are two kinds of direct broadcast methods: hole sowing and strip sowing, and hole sowing is better. The acupoint sowed on the border opened in the shape of plum blossom at a distance of 27 centimeters, with a depth of 3 to 5 centimeters, with a flat bottom and about 10 seeds per hole, scattered radially. Strip sowing in the whole border transverse trench, ditch depth of 5 cm, ditch distance of 30 cm, seeds scattered evenly in the ditch. No matter strip sowing or hole sowing, gently step on the ditch or hole, press slightly so that the seeds are closely connected with the soil, then cover the fine fertile soil about 1 cm thick, cuddle the border surface, and cover with a layer of short grass or fallen leaves for moisturizing. Usually, the seed amount per mu is 0.751kg for hole sowing and 1.52kg for strip sowing.

The seedlings of direct seeding Angelica sinensis overwinter in the field and are vulnerable to freezing damage, so some measures must be taken to protect the seedlings, such as covering the seedlings with manure before winter, watering against freezing in winter and so on.