What are the control methods for premature bolting in Angelica sinensis?

Based on the causes of premature bolting in Angelica sinensis, targeted measures can be taken to control it. The main measures are:

Starting from phase development, which is the primary condition for controlling qualitative phase changes. Starting from phase development, as long as the normal progress of qualitative change at either the vernalization stage or the photoperiod stage is controlled, premature bolting can be prevented. In production, controlling the vernalization stage is far easier than controlling the photoperiod stage. Since the vernalization stage can be controlled during winter seedling storage, when seedlings are relatively concentrated, it is convenient to carry out. That is, during seedling storage, first sterilize, control storage humidity at 60%-65%, and the temperature is best at -7-10°C.

Starting from nutritional conditions, control seedling size. According to whether the soil fertility is lean or rich, apply less or more phosphorus and potassium fertilizer, and control the seedling diameter at 0.20-0.50 cm.

Comprehensive measures should be taken in the three production links of seedling storage, seed reservation, and seedling raising for control. When reserving seeds, remove the main stem of the seed plant at the early bolting stage to promote extensive development of basal lateral branches, forming many stems with uniform growth vigor, so as to reduce individual differences among seeds and make the degree of seed development relatively moderate and uniform. On the other hand, control the maturity of the seeds, and use staged harvesting to select medium-mature milky-ripe seeds for seed reservation. The seedling storage temperature should be controlled at -7-10°C. At the same time, improve seedling-raising conditions so that the weight per 100 mu is 40-70 grams and the seedling diameter is 0.20-0.50 cm, or change the cultivation system by direct sowing in autumn, winter, or spring, or transplanting after raising seedlings in solar greenhouses; these methods can all prevent premature bolting in Angelica sinensis.

It is advocated to reserve seeds and raise seedlings yourself. At present, farmers in Min County still mainly raise Angelica sinensis seedlings on virgin land, while some farmers in river valley land can only buy seedlings from the market or raise seedlings from seeds, but the seeds and seedlings bought from the market are of unknown origin, and their low bolting rate cannot be guaranteed. Therefore, it is best to reserve seeds and raise seedlings yourself every year. If buying from the market, it is best to contact an acquaintance to ensure that the seedlings and seeds have a low bolting rate.