The Clonal Advantage at Brokaw
Since the beginning of avocado culture, innovative growers have sought the ideal avocado tree and then tried to reproduce it.
Unfortunately, early attempts were not very successful since every seed is different and the resulting trees and fruit were not particularly uniform.
More recent, the technique of grafting seedlings with buds from clones that produce superior crops has been the accepted practice. The results are the Hass, Pinkerton, Bacon, and other well-known varieties.
At Brokaw Nursery we have taken this concept a step further and applied it to developing uniform rootstocks that display a wide range of benefits. We call these clonal rootstocks. These stocks are genetically identical and exhibit uniform behavior when plated in identical situations.
The availability of Brokaw’s clonally rooted avocados lets you plant the best avocado tree for your particular situation. In short, you can custom design an avocado tree from the ground up.
Clonal propagation of rootstocks makes it possible to choose the most appropriate characteristics for your special conditions, whether these are disease-prone soils, chlorosis problems, soil and/or water saltiness or even tree size requirements.
In many cases clonal rootstocks are selected for their known tolerance to Phytophthora cinnamomi (Pc), a fungus that causes the devastating Avocado Root Rot. While it is true that a percentage of plants grown from seeds of certain varieties like Duke and G-6 possess some variable and uncertain root rot resistance, only plants that have clonal rootstocks offer definite and consistent resistance.
Duke 7, our first clonal rootstock, is moderately root rot resistant and displays the finest of growing characteristics. It has vigorous, but not rank, growth and has dark winter color and a fine record of fruit production. It is consistently a favorite among growers.
Dusa and Toro Canyon are two clonal rootstocks that possess increased tolerance of Pc. Both of these varieties show somewhat more tolerance to root rot than Duke 7 and both have slightly more vigorous growth. Dusa has an advantage in root rot resistance while Toro Canyon displays an unusual tolerance for saltiness in soil or water.
While all of these varieties display significant resistance to Avocado Root Rot (Pc tolerance), that does not mean they will thrive under all Pc infested conditions; they are not immune.
Currently, new trials of root rot resistant candidates are continuing with clones from California “survivor” trees and imports from foreign sources such as Central America, Australia, and South Africa.
Please see below for a clonal grafting illustration.