California scientists use various techniques, including grafting citrus trees under a microscope, to avoid all graft-transmissible diseases when introducing a citrus variety to the state. Because citrus trees are vulnerable to many graft-transmissible diseases, all citrus varieties to be introduced in California must by law go through the Citrus Clonal Protection Program or CCPP at the University of California Riverside. Using a grafting technique called shoot tip grafting, the CCPP will remove any disease-causing organisms and certify that a variety is healthy for release in California.
California scientists are now breeding and growing citrus from seed in order to overcome citrus disease. Scientists have discovered that some Australian native citrus relatives show natural resistance to the deadly huanglongbing (HLB) disease. Crossing these Australian citrus relatives with traditional citrus varieties has the potential to produce hybrid offspring with resistance to HLB.
This guide to growing citrus from cuttings shows how to root and graft a citrus tree in one step.
Success in rooting citrus trees from cuttings requires the proper temperature, humidity, light levels, and rooting hormone. This guide shows how to grow citrus from cuttings with a good success rate at home without a greenhouse and without accidentally bringing a deadly citrus disease into your yard.
This step-by-step guide to grafting fruit trees shows how to graft a tree using the Z-grafting technique, a technique that I have found especially useful for grafting citrus trees.
Z-grafting is a scion grafting technique that is useful for grafting trees in situations where the scion and rootstock have different diameters. I have used it in for grafting citrus when the scion diameter is greater than that of the rootstock. The Z-graft is useful both for grafting new trees and also to add new varieties to established trees.