Asexual propagation refers to the totipotency of plant cells to propagate trees with vegetative organs, which belongs to asexual propagation, such as cutting and tissue culture. His genetic material is exactly the same as his parents.
Seedlings propagated from seeds. Includes seeding seedlings cultivated with seeds in nursery and wild seedlings produced by naturally sowing mother trees in nature. The seedlings have strong vitality, developed roots, long life and easy reproduction.
However, the offspring of open pollination are prone to character separation, and the genetic characters among individuals are quite different, and the forest differentiation is serious after afforestation. In addition, the fruit-based economic forest tree species have long young age and late fruit bearing, which is also one of its shortcomings.
Seedling has the characteristics of vigorous growth, developed root system and long life. As a breeding material, it has rich sources, simple method and low cost. Therefore, seedling raising is still the most important seedling raising method in plant cultivation. In hybrid breeding, it is also necessary to use the characteristics of offspring separation of hybrid seedlings to select new varieties.
However, when fruit trees, economic plants such as rubber, butter, tung oil and some ornamental plants such as Sophora japonica and plum blossom are propagated with seedlings, products with consistent quality cannot be obtained due to the separation of traits between offspring. In addition, seedling fruit trees have a long childhood and enter the fruiting period late, and most of them are produced by grafted seedlings.
In fruit tree production, only a few tree species with stable offspring, such as papaya, hazelnut, chestnut, walnut and some citrus fruit trees, still use seedlings directly, and most rootstocks used for grafting use seedlings of their relatives.
To cultivate healthy and tidy seedlings, we must choose excellent mother trees and harvest fully mature seeds in time. The water content of seeds during storage should not be higher than 65438 02%, and the temperature should be kept at about 5℃. Some seeds that are not suitable for dry storage, such as chestnut, litchi and citrus, should be stored in low temperature and wet sand.