Cross breeding of Carnation

Carnation (Dianthuscaryophyllus), also known as carnation (Carnation), belongs to the genus Carnation of Carnation family. The flower color is delicate and beautiful, and the flowering period of a single flower is longer, so it is an important cut flower plant in contemporary times. Carnation originated in southern Europe, the northern shore of the Mediterranean, France to Greece, now widely cultivated all over the world, mainly in Italy, the Netherlands, Poland, Israel, Colombia, the United States and so on. With the commercial production of carnation, there are many companies specializing in breeding and breeding. These companies have their own advantages in variety types, and can launch a certain number of new varieties every year to enhance market competitiveness, and at the same time inject stronger vitality into the sustainable development of carnation flowers. The breeding of carnation in China started relatively late, and most of the popular varieties in the domestic market are imported foreign varieties. at present, after years of breeding research and development in Shanghai Flower breeding Center, several carnation varieties with independent intellectual property rights have been cultivated. Based on my own practical experience, the author briefly introduces the cross breeding method, which is the most commonly used and effective method for the breeding of new carnation varieties.

Breeders must understand the habits, classification, breeding objectives and development of carnation before breeding.

Variety classification

The variety classification of carnation has various classification standards, which can be divided into two categories: potted flower (flower bed) carnation and cut flower carnation. The former was all the rage 150 years ago, but now there are only a few varieties, but there is a momentum of growth, while the latter is the main cultivated and applied variety at present. According to the flower pattern (inflorescence), carnation can be divided into regular flower carnation or single head carnation (Standardcarnation) and multi-flower (multi-flower, floret) carnation (Spraycarnation). The former retains one branch and one flower, while the latter has many branches and flowers. According to the size of flower stem, it can be divided into four types: large flower (8-9cm), medium flower (5-8cm), floret (4-6cm) and mini flower (2.5-3cm). According to flower color: pure carnation (Clove), petals without miscellaneous colors, mainly white, pink, rose red, bright red, crimson to purple, milky yellow to yellow, orange and other colors; discolored carnation (Bizarre) has more than two different colors on one background, spreading spots or marks directly to the edge from the petal base; two-color carnation (Flake), in a background color, only one kind of heterochromatic self-petal base spreads to the edge. Striped carnation (Picotee), with a narrow ring of different colors on the edge of the petals and the rest in solid color. According to its origin, it can be divided into two categories: Sim system and Mediterranean system.

Breeding goal

The breeding goal of carnation is not only ornamental characters, but also horticultural characters. Ornamental characters require bright flowers, no drooping outer petals, no pistils, fragrance, full petals and can bloom at the same time; calyx is not easy to fall off, flowers are persistent; pedicels are straight, culms are hard, flexible, not easy to break; leaves are large, attached wax layer, not curled, not dry; flower branches are symmetrical, axillary bud sprouting node is low, secondary flower is early; root system is strong. In terms of ecological breeding, the goal of carnation breeding in Europe is to grow and blossom under weak light in winter, while in Japan it is mainly to cultivate heat-tolerant varieties with no decrease in growth quality under high temperature in summer, while both are needed in China. From the point of view of disease resistance breeding, the disease caused by Fusarium wilt (Fusarium) is serious in Europe, while the bacterial spot problem caused by Pseudomonas (Pseudomonas) is more serious in Japan. At present, the leaf spot disease caused by Altemaria is more common and serious in China. Disease resistance breeding has become an important goal of carnation breeding. In addition, heat tolerance, early maturity and high yield are also important goals in carnation breeding research.

Cross breeding technique

Pollen is an important condition for the selection of male parents. Carnation is a double flower, which is made from stamens and is not easy to collect; the pistils of most varieties are normal. Using the existing varieties, interspecific hybridization can be carried out with the original species of Carnation with disease resistance. Cross breeding requires years and months of perseverance, and the division of labor and cooperation among all parties is very necessary.

The main operating procedures of cross breeding are as follows:

Parent selection → mating → seed collection → seed → flowering selection → vegetative propagation (cuttage)

Basic hybridization techniques:

1. Usually, the female parent should carefully remove the petals and stamens when the petals are exposed, and then put on a paper bag to prevent foreign pollen pollution.

2. It is suitable for pollination when the air is dry and the temperature is 18 ℃-25 ℃ from September to November and from March to April. The suitable period of pistil pollination is in the middle and later stage of flowering, and it is better when the stigma is bifurcated, shiny and mucilaginous. The effect of pollination is good, and the method of repeated pollination can be used.

3. After pollination of each flower, pollination tools (tweezers or brushes) must be sterilized with 75% alcohol; bag in time and hang a sign indicating the name of the parents' hybrid combination, date of hybridization, etc.

4. Generally, about 10 days after hybridization, bagging can be removed for ovary development and growth. Fertilizer and water management and pest control should be strengthened for hybrid plants, especially the application of potassium and boron fertilizer, which is beneficial to seed maturation. Usually after 40 min 50 days, when the top of the inflated ovary changes from green to brown, it indicates that the seeds are mature and should be harvested in time. The harvested seeds are stored in combination together with the signs to prevent mixing and store the seeds in a drying dish.

5. The treated seeds can be sown in flowerpots or seedling trays in greenhouse and kept at room temperature for 20 ℃-25 ℃. When the seedlings grow into 3 pairs of true leaves, the seedlings are transferred once, and the nutrient solution is sprayed on the leaves once a week after the seedlings are transferred. When the seedlings reach 8-10cm, they can be planted on the cultivation bed.

6. Plant treatment: after planting, the seedlings were carefully managed without coring, and 5 lateral buds were left at the base, so that the terminal buds blossomed first, and the useful hybrids continued to self-cross or backcross, so as to stabilize the characters and expand the production of seedlings by asexual reproduction. The individuals with poor growth and slow growth in seedlings should be pulled out as soon as possible. Because of the heterozygosity in the genetic composition of carnation, the offspring will be different from their parents. The first selection was made during flowering, and the selected individuals with excellent flower color and shape were propagated by cutting, and then selected (this is clone selection). Finally, a new variety with excellent comprehensive index was obtained and popularized by tissue culture.