Sweet Oranges - Cultivation - Propagation

Propagation

It is possible to grow orange trees directly from seeds, but they may be infertile or produce fruit that may be different from its parent. For the seed of a commercial orange to grow, it must be kept moist at all times. One approach is placing the seeds between two sheets of damp paper towel until they germinate and then plant them, although many cultivators just set the seeds straight into the soil.

Commercially grown orange trees are asexually propagated by grafting a mature cultivar on to a suitable seedling rootstock to ensure the same yield, identical fruit characteristics and resistance to diseases throughout the years. Propagation involves two stages: first, a rootstock is grown from seed. Then, when it is approximately one year old, the leafy top is cut off and a bud taken from a specific scion variety is grafted into its bark. The scion is what determines the variety of orange, while the rootstock makes the tree resistant to pests and diseases and adaptable to specific soil and climatic conditions. Thus, rootstocks influence the rate of growth and have an effect on fruit yield and quality.

Rootstocks must be compatible with the variety inserted into them because otherwise the tree may decline, be less productive and even die.

Among the several advantages to grafting are that trees mature uniformly and begin to bear fruit earlier than those reproduced by seeds (3 to 4 years in contrast with 6 to 7 years) and that it makes it possible to combine the best attributes of a scion with those of a rootstock.