A brief discussion on the degradation of Flower varieties and Preventive measures, and the introduction of Edible Fungi

With the development of flower production, the formation of industrialization, the introduction of new varieties and the increase of breeding varieties, as well as the unreasonable operation in the process of seed propagation and utilization, the degradation of flower varieties has been more serious, which has a great impact on the development of flower industry. it is urgent to pay attention to and solve it.

The degeneration of flower and plant varieties

The process and performance of weakening the original excellent species of flowers and plants is called variety degradation. After the superior varieties were degraded, the characters became worse, such as morphological distortion, growth decline, flower color disorder, smaller flower diameter, lower double petal, different florescence, poor resistance and so on.

Reasons for the degradation of varieties

There are many reasons for the degradation of flower and plant varieties, which are mainly as follows:

1. Biological hybrid

Most of them occur in annual or biennial flowers propagated with seeds. Other genotypes were mixed in the process of seed collection, seed drying, storage, packaging, transportation, sowing, seedling raising and transplanting, or improper distance, resulting in natural hybridization, resulting in gene recombination and separation. This phenomenon is most likely to occur among varieties with similar seeds or branches and leaves, such as sweet pea, petunia, lupine and so on. Biological mixing occurs most easily between varieties or species of outcrossing plants and often outcrossing plants, and also occurs among self-pollinated plants, such as hollyhock, cockscomb, impatiens, tricolor Dong, marigold, chrysanthemum, goldfish grass and so on.

two。 Genetic deterioration

This variation is caused by a mutation in the allele. For example, the red Corolla of Celosia cristata is controlled by dominant gene and yellow by its allelic recessive gene, when the dominant gene controlling red is mutated to allelic recessive gene, the Corolla changes from red to yellow, on the contrary, if the recessive gene is mutated to allelic dominant gene, the color of Corolla changes from yellow to red. If the mutation occurs later, there is a red-yellow mosaic phenomenon, some atavistic inheritance, lose a large Corolla and become the original cyan inflorescence. This phenomenon is common in flowering plants.

3. Virus infection

Virus infection is very common in flowers and plants, and the loss is also very serious. At present, it has been found that the flowers caused by the virus are canna, tulip, gladiolus, lily, chrysanthemum, dahlia, cyclamen, carnation, rose and so on. For example, after the canna was infected with cucumber mosaic virus, the early leaves appeared small green spots, and in severe cases, the leaves were curled, deformed, the flowers were broken, the plants were short, and even withered; after the lilies were infected with the mosaic virus, the leaves curled backward, the plants were short, and the flowers were deformed, and even could not bloom normally. Virus infection is generally transmitted by piercing and sucking mouthparts insects such as aphids, thrips, leafhoppers, planthoppers, etc., and can also be caused by wound contact infection caused by grafting, heart-picking, power-beating and other operations.

4. Improper methods of reproduction

For example, the capsule size of goldfish grass and petunia decreases upward from the lower part of the inflorescence, the seeds of radiating flowers of Persian chrysanthemum are large and heavy, and the seeds of middle flower are light and small, if they are propagated with the seeds of upper or middle flower of inflorescence, the seedlings will be thin and grow poorly, and the seeds of five-colored cockscomb and twisted impatiens have not been collected in typical inflorescence parts. Or dichromatic foliage plants, such as Cymbidium, Euphorbia angustifolia, Camellia oleifera, Euphorbia angustifolia, Populus tomentosa, etc., cut off the organs without typical characters for cutting, often losing their original typicality.

5. Degradation caused by discomfort of cultivation environment

Such as cold and cool dahlias, gladiolus, etc., if cultivated in hot and humid areas, often grow poorly, flowers become smaller, inflorescences become shorter; and if shade-tolerant flowers are planted in places with too strong sunlight, the quality of flowers will be greatly reduced.

Technical measures to prevent the degradation of Flower varieties

In view of the causes of the degradation of flower varieties, the work of impurity prevention and purity protection should be done in practice.

1. Prevent confusion

Prevent mechanical mixing: to prevent mechanical mixing, we should pay attention to the following links:

(1) seed harvesting: seeds dropped on the ground should be harvested in time so as not to be mixed. Seed harvesting should be marked with variety name inside and outside the harvesting apparatus, and seeds without a variety name label should be discarded afterwards.

(2) seed drying: when drying seeds, the containers of each variety should be separated at a certain distance, and more attention should be paid to the seeds that are easily moved by the wind. In the case of a small amount, it is best to put them in a bag to dry.

(3) sowing and raising seedlings: when sowing, choose windless weather, the seeds are too light, you can add a little fine soil or fine sand to drop seeds, similar varieties had better not raise seedlings in the same border, slow down when pouring water into the border so as not to wash away the seeds, after sowing, immediately insert a sign and draw a planting map.

(4) transplanting: this process is the most easy to be mixed, so it is necessary to raise seedlings according to the planting map, try to finish planting one variety, plant another variety, insert a sign in time, and draw a good field planting map.

(5) impurity removal: impurity removal was carried out several times in each period of field development, which is an effective measure to prevent mechanical mixing, which can be carried out once in transplanting, planting, first flowering, full flowering and last flowering stage.

Prevent biological confusion: the basic way to prevent biological confusion is isolation. There are three methods of isolation:

The main results are as follows: (1) Spatial isolation: the distance of spatial isolation varies with wind force, wind direction, pollen quantity, pollen flying degree, double petal degree, sowing area and so on. Generally speaking, the isolation distance is larger in the open area where the amount of pollen is large, the degree of double petal is small, the wind is strong in the breeding season, the sowing area is large and lack of obstacles. When the area is small, sunny beds or isolation covers can be used to prevent insect pollination. The isolation distance should also take into account the natural hybridization rate of species, such as cockscomb, morning glory, marigold, marigold, zinnia, hollyhock, carnation, etc., the isolation distance should be more than 300m.

(2) time isolation: time isolation is the most effective way to prevent biological confusion. Time isolation can be divided into two types: cross-year and non-cross-year, which are sowed monthly in the same year, planted in stages, and staggered the florescence of different varieties. This method is suitable for some species that are not sensitive to photoperiod. For example, chrysanthemum can be sowed in autumn and flowered in spring and autumn. A bunch of red, impatiens, morning glory and other suitable sowing period is longer, different varieties of wrong time sowing, supplemented by topping for seed reproduction is also a feasible method. Annual isolation means that all varieties are divided into two or three groups, and the hybridization rate among varieties in each group is not high. Only one group is sown each year, and the seeds are properly preserved for two or three years. This method can be used for species or varieties with long effective storage period of seeds.

(3) isolation of obstacles: natural barriers such as forests, tall crops, tall buildings and conscious isolators can be used to isolate foreign pollen transmission sources.

two。 Select seeds or vegetative organs with high typicality for reproduction

Practice has proved that seeds in different positions in the same inflorescence have different typicality of their offspring, such as Persian chrysanthemum, chrysanthemum, cornflower, marigold and other flowers, and the seeds planted on the edge of the disk can most accurately inherit the flower shape and color of the female parent. Asexual reproduction flowers should select typical leaves, flowers, branches and other parts for cutting, grafting or tissue culture, and propagate with young foot buds as far as possible, which is beneficial to maintain the species character of the variety.

3. Strengthen field management

Fine field management is very important to improve the species character of flowers and plants, such as pulling out virus-carrying plants, eliminating pests, avoiding continuous cropping, strengthening fertilizer and water management, and creating environmental conditions for the full development of characters for fine varieties; for the species that propagate with seed bulbs, bulbs, tubers and other organs, the yield can be increased and the quality of seed parts can be improved by topping and pruning.

4. To provide a suitable cultivation environment for varieties according to their seed conditions.

It should be suitable for flowers in suitable land and season, and flowers that like cold and cool, such as Gladiolus, can be cultivated in autumn in the south to prevent the degradation of varieties.

5. Timely purification and rejuvenation

After it is found that the varieties have the phenomenon of hybrid degradation, it is necessary to carry out purification and rejuvenation in time to avoid further accumulation of bad characters. In each period of flower growth and development, observation and comparison were carried out, and the method of individual plant selection was used for purification to achieve the purpose of rejuvenation.

Although the improved varieties can be restored under certain circumstances, it is a complex and difficult thing, and it takes a long time, and some varieties are even difficult to recover after degradation, so in the use of varieties, we should focus on preventing impurity and keeping purity. Carry out the policy that impurity prevention is more important than impurity removal, and purity is more important than purification.