IN VITRO PROPAGATION OF RHODODENDRON
Our early experience with tissue culture of Rhododendron was in the late 1960's with Dr. Wilbur Anderson of the Western Washington Research Station. Major advantages of tissue culture is the rapid increase and introduction of new selections from around the world. Rhododendrons can be produced from the following explants: vegetative meristems, vegetative shoots, or flower buds. A low mineral salt medium such as Anderson's Medium (AM) or Woody Plant Medium (WPM) supplemented with appropriate growth regulators is used to initiate growth and production of juvenile shoots. Vegetative material is sterilized using dilute sodium hypochloride. Various other sterilization agents will be presented. Explants are grown in an environmentally controlled room with temperatures of 21–23° C., and light levels of 100–400 foot candles. Shoot multiplication rates of 3x to 20x can be achieved with Rhododendron. Particular attention needs to be paid to the quality of microshoots produced as it directly affects the rooting percentage. Rhododendrons can be rooted in vitro. A low mineral salt medium such as half strength AM or WPM supplemented with 600 milligrams per liter activated charcoal with 5 milligrams per liter indole-3-butyric acid (IBA) can be used to root Rhododendron in vitro. Due to economic reasons, most of our rooting is accomplished outside of the laboratory. Tissue culture has increased the rate of distribution of new selections and difficult to propagate rhododendrons worldwide. Tissue culture will remain an important tool for the plant propagator to use with these and other plants. Shoot tip micropropagation may some day be replaced by somatic embryogenic methods now being researched.
Briggs, B.A., McCulloch, S.M. and Caton, L.A. (1994). IN VITRO PROPAGATION OF RHODODENDRON. Acta Hortic. 364, 21-26