In according to place, to have success in the propagation, if the knowledge needs the structure and the mechanisms of growth of the plants. This if can say that it constitutes? science of the propagation. The spreader can acquire part of this information in empirical way when working with the proper plants, but it must be completed with formal courses of botany, horticulture, genetics and vegetal physiology. This knowledge helps the spreader to understand because of the things that make, to execute them better and to solve problems unexpected. One third requirement to be to have success in the propagation of plants, is to know the diverse classrooms of them and some methods with that they can spread. To a large extent, the used method must be adjusted to the classroom of plant that if propagates and to the conditions where if it carries through.
The propagation of plants is a basic occupation of the humanity. Probably the civilization if initiated when the old man learned to sow and to cultivate certain types of plants that satisfied its nutritional necessities and of its animals. In the measure where it advanced the civilization, it was adding to the diversity of plants other cultivos, not only nourishing, but also those that provided flowers, medicines, leisure and ornamentao to it. The improvement of the plants at the time current was preceded by a great progress in the election of the same ones. Our cultivated plants if had originated mainly for three general methods.
First some had been selected directly of wild species, but, under the care of the Man, they had evolved? types? that they differed completely from its ancestral Sylvesters; as example of this group the tomatoe, the barley and the rice can be cited. Second, others had originated for hibridao between species, folloied of changes in the number of chromosomes. In this group if they find the maize, the wheat, the tobacco, the pear tree and the plum tree. Third, it appears another group of plants whose rare forms differ from excessively from its species and which, even so inadaptadas to a natural environment are useful to Man; between them they are the cabbage, the broccolis, borecole-of-Brussels. However, this progress in the improvement of plants would have lacked of importance the least that, simultaneously, if makes use of methods to keep in culture the improved forms, which originated a process of invention and discovery of techniques for propagation of plants. Most of the cultivated plants if would lose or revert the forms less desirable, the least that if propagated in controlled conditions capable to preserve its characteristics. Through the time, in the measure where if it has made use of new types of plants, if they had developed techniques to keep them, as if it advanced in the propagation methods, has increased the amount of available plants for culture. An ideal type of propagation for the majority of the fruitful plants is the vegetative one, that is, that one in which one has left of the plant, already in production, either one bubbles, one breaks, a prop or a branch (yoke), is used to originate a new plant. Many plants, however, must or can be propagated by seeds, but almost always he is disadvantageous. The propagation for seeds is used when the ways of vegetative propagation are not possible, as for the coconut palm and other palms, that can be propagated way seed, or other plants, in which the seminfera propagation does not bring many problems to its culture, as the mamoeiro, maracujazeiro, or species that are precocious.