Production of cut tulip flowers and prevention of blind flowers

Tulip (Tulip sneria L.) Another name is lotus, grass musk, lily tulip is perennial bulbous ornamental flowers, is one of the world's famous flower varieties, known as "the king of flowers" said [1,2,3]. The technology of box cut tulip flower production, the cause of blind flower formation and the prevention technology are still relatively backward in China, which restricts the development of cut tulip flower production. While vigorously developing tulip soilless culture, the flower base of Hebei Province Academy of Forestry has carried out preliminary research on biological characteristics, root urging treatment, growth period management and pest control in soilless culture methods [4]. On the basis of referring to related literatures and combining with production practice, this paper mainly discusses the production technology, causes and prevention of blind flowers of cut tulips in box, aiming at providing effective scientific basis for promoting the standardization, internationalization and commercialization of cut tulips production in China.

Production technology of cut tulip flower

Box culture of tulip

Cut tulip flowers were produced in 60cm×40cm×20cm plastic boxes or wooden boxes with gaps around the boxes. Coarse sand and vermiculite with excellent permeability and water retention were suitable for matrix. The substrate must be sterilized by insolation during planting. The planting adopts three-layer cultivation method [5], that is, the upper and lower layers of the box are coarse sand, the thickness is 3cm and 6cm respectively, and the middle layer is vermiculite, the thickness is about 8cm. Tulip box cut flower production should be 9℃ bulb, flowering should be controlled. When planting, 4/5 of the seed balls should be placed in vermiculite, and the planting density should be 400/m2, that is, about 100 seed balls per box. Tulips have phototaxis during growth, and the direction of the box should be adjusted in time. After watering with enough water, root promotion treatment is carried out under dark condition, the temperature is controlled at 9 - 11 DEG C, and the moisture content of the substrate is kept at 90%-100%. Rooting takes 4 - 6 weeks. It takes 25~35 days (depending on the variety) to flower after rooting, and the time of transplanting into greenhouse is determined according to the need of flower use. During the growth period, the temperature is controlled at 15~20℃, and the relative humidity (RH) of the air is controlled at 60%~70%, which can alleviate the RH in the greenhouse, help the plant to maintain a dry state, effectively inhibit the infection of germs, and reduce the occurrence of diseases. Under the condition of promoting cultivation, tulip growth and flowering mainly depend on the nutrition stored in the bulb itself, and generally do not need fertilizer.

harvesting time

Tulip flower development to translucent, that is, flower color is fully formed when the best harvest period. Harvesting time is generally selected at 7~8 am or 5 pm. During flowering, wait until the flowers close at night before harvesting.

dribble harvesting

When harvesting, pull out together with the ball, that is, harvest with the ball, and retain the base 2~3 leaves. Harvesting with the ball can reduce the spread of soil diseases; the storage time of flowers and plants can be prolonged; if the height is not enough, the stem (2~3cm) can be used to make up enough height. The height of cut tulips is generally 45~70cm.

postharvest finishing

After harvest, put it in cold storage at 2~3℃ and RH90% for 2 hours, then remove the ball, bundle the flower head in the same direction, generally 10 pieces into a bundle, 5 bundles into a packet wrapped with newspaper, put it into water, the water temperature is 1~2℃, and the water absorption time is about 24 hours. When stored in cold storage, it should be placed vertically and protected from light to prevent plants from bending. The storage time should not exceed 3 days, otherwise the quality of flowers will be affected.

Causes and Prevention of Blind Flowers

Blind flower is a physiological phenomenon caused by the quality of seed bulb or the environmental conditions during the growth period, which causes the flower buds not to be pulled out or shriveled after pulling out, and it is the biggest obstacle in tulip production.

blind flower formation

The main reasons for the formation of blind flowers are:

(1) Quality problems of seed balls. One is that the bulb is not completely differentiated and the cold treatment begins when the storage nutrition is insufficient; the other is that the quality of the bulb is poor due to insufficient cold treatment time or improper temperature control (the appropriate temperature is 17~20℃), and the flower bud development is not good, resulting in blind flowers during growth.

(2) Bad root system. It is mainly caused by high or low temperature, water shortage and insufficient rooting time during the rooting treatment, which results in short roots and weak water absorption capacity, and causes blind flowers in the later stage.

(3) Environmental discomfort. During the growth period, high temperature and high humidity caused excessive growth of plants or continuous drought twice, which easily led to the production of blind flowers.

Prevention of Blindness

The prevention of tulip blind flower should focus on the quality of seed bulb, root treatment, strengthen the management during the growth period, and comprehensively prevent the occurrence of blind flower. In production, the following work should be done according to the causes of blind flowers:

(1) Select high quality seed balls. Before planting, the seed bulbs were sampled strictly to check whether the flower bud differentiation was completed and whether the development was normal, so as to determine the quality of the seed bulbs and the blind flower rate.

(2) During the rooting period, strictly control the temperature at 9~11℃, keep the substrate moisture at more than 95%, strictly carry out the rooting treatment under the dark condition, promote the robust growth of the root system, and when the root system is about 10cm long, start to move into the heated greenhouse and start the growth of the aboveground part. Because the root system of tulip is fragile and has no regeneration ability, blind flowers caused by damage of root system should be avoided in production.

During the growth period, control the temperature of the greenhouse at 15~20℃, and when it exceeds 25℃, ventilate and cool down in time. Watering once every 3~ 4 days on average, controlling the moisture content of substrate above 90% to avoid drought.

summary

Tulip box culture has the advantages of effective use of space, saving a large amount of land, greatly improving flower yield per unit area, good mobility, effectively solving the problem of plant phototropism, avoiding cross infection of pathogens, etc.

The procedure of harvesting cut tulips: harvesting with the ball-→ storing in cold storage (2~3℃)-→ removing the seed ball bundle packaging-→ storing the tulips to be sold in cold storage (below 5℃)-→ selling.

Besides the quality of bulbs, the main causes of blind flowers are water deficit caused by poor root development and environmental discomfort. The prevention focuses on good bulb quality, good root urging treatment, strengthening temperature management during growth, and maintaining sufficient water, which can effectively reduce the occurrence of blind flowers.

Box cultivation tulips can also be used for potted plants, that is, when the flowers are slightly colored, transplanted into pots to minimize root damage. After planting, put it in the shade, control the temperature at about 10℃, and sell it after 2~ 3 days.