How do roses reproduce

Rose belongs to the family Rosaceae and is a deciduous shrub. It is a spice tree species and common flowering tree with high economic value. The flowers contain about 0.03% of essential oils, which can extract high-grade aromatic oils and extract essences. They are the main source of fragrance for the food industry and cosmetics. The petals can be used as raw materials for the food industry; the flower buds, fruits, and root bark can be used as medicine. Roses have lush foliage, numerous flowers, bright colors, and rich fragrance. They are an excellent tree species for garden viewing and greening and beautifying the environment. Because of its strong germination ability, rapid growth, cold and drought resistance, and strong ability to prevent wind and sand fixation, it is also one of the pioneer tree species for greening sandy wasteland. Rose propagation methods are divided into sexual propagation, asexual propagation and tissue culture. Asexual propagation is further divided into cuttings, grafting, divisions, layering, etc. The rose propagation methods and technical points are described below:

Sexual reproduction

Seed treatment

Soak the rose seeds in clean water for 48 hours, then mix them thoroughly with wet sand (the humidity of the sand is measured by holding the sand into a ball and letting it go) (seed to sand ratio 1:3), and stratify for 30 hours in an environment below 5°C. ~50d.

Sowing

Sow seeds from late March to mid-April after the soil is completely thawed. Use flat furrows and drill sowing methods with a furrow distance of 20-25cm. Water the furrows. After the water seeps out, sow the germinated seeds into the furrows. The soil covering thickness is 1-1.5cm and the seeding rate is 8-109/m2.

Post-broadcast management

Generally, seedlings begin to emerge in 15 days, and the height of the seedlings is about 5cm. It is advisable to keep the spacing between plants at 10 to 15cm. Strengthen water and fertilizer management. In autumn, the base diameter of the seedlings can reach more than 0.5cm and the height can be more than 30cm. They can be planted out in the following spring. Pay attention to the prevention and control of diseases and insect pests during the growth process. After all the seedlings have emerged, spray 1000 times phoxim solution on the whole plant and on the ground to control chafers.

Asexual reproduction

Asexual propagation of roses is divided into cuttings, grafting, divisions, layering, etc. Cuttings are further divided into hard branch cuttings and twig cuttings according to different seasons.

Hard branch cuttings

Carry out in conjunction with fall pruning. Cut the pruned branches into 15-20cm cuttings. The lower cut is 0.5-1cm away from the lower bud and cut into a horse-ear shape. The upper cut is 1cm above a full bud at the top. Cut the cuttings at 50-100mg/L Dip in naphthalene acetic acid talcum powder paste (add 0.5‰ carbendazim) to a depth of about 2cm. The lower end of the cuttings should be evenly dipped in the paste, and the cuttings should be placed in a solar greenhouse or insulated sunny border. The substrate should be fertile. Sandy loam soil, pay attention to heat preservation and moisture retention. In the spring of the following year, after the cuttings take root, they can be hardened through ventilation and transplanted to the field in mid- to late April.

Young branch cuttings

It can be carried out throughout the growing season, with the highest survival rate for cuttings from June to August.

2.2.1 Make a bed: Make a cutting bed with a width of 1 to 1.2 m and a length of 10 m. The substrate is 20 cm thick pure river sand. Build a 1.5 m high shade shed on the bed with a shading rate of 50% to 75%. network coverage. The river sand is disinfected with 0.1% potassium permanganate solution before cutting. The dosage is 59/m2, and sprayed with clean water after 15 minutes. Units with conditions can adopt full-light spray seedling cultivation technology and equipment.

2.2.2 Cuttings: Cut the semi-lignified branches of the current year into 10-15cm cuttings with 3-4 full buds on them. Remove the leaves at the base and retain 2-3 compound leaves on the upper part. Cut the lower cuttings into For the horse-shaped scion, dip it in 500-800 mg/L naphthalene acetic acid alcohol solution for 5-10 seconds or soak it in 50-100 mg/L ABT No. 1 rooting powder alcohol solution for 1 hour. Take out the scion and cut it after the alcohol evaporates. The insertion depth is 3-3. 5cm, with a density of 150 to 200 plants/m2. Spray water while inserting. After inserting a bed, spray it once to make it permeable. Insert a bamboo pole arch with a height of 80cm on the bed and cover it with plastic film to keep warm and moisturizing.

2.2.3 Post-insertion management After coating, keep the temperature in the shed at 20-30°C, the air humidity at 80%-90%, and the substrate temperature at 20-23°C. Pay attention to frequent spraying of water to humidify and cool down. Generally, healing will begin in 7 days. Tissue, the rooting rate reaches more than 80% in 20 days. After the cuttings take root, spray 0.2% potassium dihydrogen phosphate solution on the leaves. After 30 days, gradually reduce the number of water sprays, ventilate the seedlings, and finally remove the cover before transplanting. . During the entire cutting process, spray 800 to 1000 times of 50% carbendazim wettable powder on the leaves every 7 to 10 days to prevent rose diseases.

Grafting

It can be carried out before roses germinate in early spring, axillary buds form in summer and before growth stops in autumn (i.e. mid-March, mid-July, mid-September), but bud grafting is mainly done during the growing season. Japanese thornless rose is used as the rootstock, and methods such as “T-shaped” bud grafting or xylem inlay bud grafting are used. For bud grafting, the full axillary buds in the middle and upper part of the rose branches that germinated in the current year should be used. The leaves should be removed, and the petioles of about 1 cm should be retained. When grafting is less than 5cm and the epidermis is smooth, pay attention to the alignment of the cambium layer, and then tie the plastic strips. When tying the plastic strips, tie them tightly and tightly. Finally, break the rootstock branches 10cm away from the upper end of the grafted buds, but do not break or cut them off. Keep an appropriate amount of leaves on the upper end of the rootstock to facilitate joint healing. Check the survival situation after 10 to 15 days: fresh buds and petioles that fall off at the touch prove that the graft has survived. Those that have not survived should be replaced in time. Untie it when the interface is fully healed and the grafting buds have sprouted. When the grafting buds grow to 10-15cm, cut the anvil 1cm above the interface and wipe off the rose anvil buds at any time.

Ramets

Roses have strong tillering ability, and division is the traditional method of raising seedlings. It can be done from after the leaves fall in autumn to before germination in spring. Dig out the entire rose bush and divide it into several small plants with a sharp knife according to the root growth of the sprouting tillers. Each small plant should have a considerable number of fibrous roots, more than 2 branches above ground, and the wound should be as small as possible. Apply plant ash to the wound and plant it directly into the field.

Layering

Can be done throughout the growing season. ． From May to September, select lignified 1-2a strong branches near the ground, bend the middle part of the branches and bury them in the soil, and use a knife to carve the branches into the soil (the carving site is 0.5-1cm below the buds) , reaching deep into the xylem, stimulating rooting in this part, and can also be continuously layered as the branches grow. After the leaves fall in autumn, dig out the new plants that have taken root and plant them separately.

Tissue culture

Explant sterilization

Select disease-free, healthy branches with axillary buds, rinse them with running water, cut them into stem segments with one axillary bud about 1cm long on a clean workbench, and soak them in 70% alcohol for 5 to 10 seconds, 0.1% Sterilize with HgCl2 for 8 to 12 minutes, and finally rinse with sterile distilled water 5 times.

First generation culture

Inoculate the stem segments into 1/3MS+6-BA 1. Omg／L+IBA O． In 02 mg/L medium, axillary buds began to sprout and grow around 7 days.

Differentiation and proliferation

After the young shoots unfold their leaves, cut the young shoots and inoculate them into the culture medium of MS 16-BA2.0 mg/L+gas A0.15 mg+sucrose 40 mg/L+agar 69/L. The young shoots will begin to differentiate in about 15 days. Clusters of buds.

Rooting and transplanting

Cut off the clustered buds and insert them into 1/2MS+N’ cricket D. 5 mg/L culture medium can take rooting in about 25 days. Plant the rooted seedlings in the bottle for 5 to 7 days, wash away the culture medium, and then plant them into vermiculite. Cover with film to keep them warm, keeping the temperature at 25 to 30°C and the humidity at 80% to 90%. After 20 days, gradually remove the film until it is completely removed, and then transplant it into a nutrient bowl or field.

Analysis and evaluation

Complete rose plants can be obtained through the above methods, but various methods have differences in retaining the genetic traits of the variety, reproduction coefficient, flower production, equipment investment, etc.

Sexual reproduction

The quality of the seeds determines the quality of the seedlings. It is difficult to ensure that the excellent traits of the variety are completely inherited in the resulting seedlings. It takes 2 to 3 years for the seedlings to bloom, and the results are slow. This method is mostly used in the breeding of new varieties and the purification and rejuvenation of varieties.

Asexual reproduction

Various methods of vegetative propagation can maintain the genetic traits of the variety, with a high survival rate, strong plant growth, and flowering in the same year or the next year. Among them: cuttings are easy to root, facilities and operations are simple, seedlings are grown quickly, and the reproduction coefficient is large; grafting saves seed strips, grafted seedlings grow quickly, and produce high flowers; seedling cultivation by division is highly seasonal, affecting flower production and the reproduction coefficient is low. It cannot meet the needs of mass production; the survival rate of layering seedlings is the highest, but the reproduction coefficient is low, and it increases the labor intensity of the rose garden and affects the amount of flowers produced.

Tissue culture

The reproduction coefficient is large, the seedlings emerge quickly, and the excellent traits of the variety are completely retained. However, special equipment is required for tissue culture, and the equipment investment is large, so it is not suitable for use in grassroots production units. Tissue culture is mostly used in the propagation and virus-free rejuvenation of fine varieties with few provenances. The above analysis shows that among the methods of propagating roses, cutting and grafting have the characteristics of fast emergence, simple operation, saving labor and time, and low investment, and are worthy of promotion in production.