Avocados do not come true from seed; that is, a tree grown from a seed of the Trapp variety will not produce Trapp fruits, although it may produce fruits similar in character. For commercial purposes it is necessary to propagate the trees by budding or grafting, in order to insure good fruit of uniform quality and to eliminate sparse bearers, or trees otherwise undesirable.
Seedling avocados are often grown, especially in the tropics. While named varieties cannot be propagated in this way, if the seed is taken from good fruit the tree which it produces is likely to bear such fruit. But occasionally seedling trees do not bear, and some have other undesirable qualities, so that it is always best to plant a budded tree. Seedlings can only be recommended, in fact, where a tree is desired for the dooryard merely, in which case the ornamental appearance of the avocado makes it eminently satisfactory. If such trees do not bear well no special loss is entailed.
Since 1901, when George B. Cellon first budded the avocado commercially, several methods of vegetative propagation have been applied to this plant by nurserymen. While all of these have been successful in the hands of certain propagators, shield-budding, which was originally used by Cellon, has proved the most generally dependable, and is now employed by most nurserymen in California and Florida. It is, therefore, given major consideration here, while methods of grafting are described in less detail.