Although most Rhododendrons are diploids having 26 chromosomes, diploid, triploid, tetraploid, pentaploid, and even higher ploidy level Rhododendrons do exist.
Although most Rhododendron species are diploids, tetraploid Rhododendron species exist.
Summary of Ploidy Levels for Rhododendrons
Diploid - 26 chromosomes
Triploid - 39 chromosomes
Tetraploid - 52 chromosomes
Pentaploid - 65 chromosomes
Hexaploid - 78 chromosomes
Octaploid - 104 chromosomes
Summary of Expected Outcome from Normal Rhododendron Crosses
Diploid X Diploid yields Diploid
Tetraploid X Tetraploid yields Tetraploid
Diploid X Tetraploid yields Triploid
Summary of Known Outcomes from Rhododendron Crosses
Diploid X Diploid yields Diploid, Triploid
Tetraploid X Tetraploid yields Tetraploid
Diploid X Tetraploid yields Diploid, Triploid, Tetraploid
Diploid X Triploid yields Diploid, Triploid, Tetraploid
Triploid X Tetraploid yields Triploid, Tetraploid, Pentaploid
John and Sally Perkins
