Rhododendron 'Pink Pearl', which is a Waterer hybrid documented as 'George Hardy' x 'Broughtonii', has been determined to be a triploid using flow cytometry by
Dr. João Loureiro, Dr. Silvia Castro, José Cerca, and Mariana Castro
Plant Ecology and Evolution Group
Centre for Functional Ecology
Department of Life Sciences,
Faculty of Science and Technology,
University of Coimbra.
'Pink Pearl' is sometimes referred to as the first commercially successful Rhododendron.
Other flow cytometry results from this research team include the following
'Broughtonii', the documented pollen parent of 'Pink Pearl', is a triploid.
'Antoon van Welie', which has 'Pink Pearl' as a documented seed parent, is a tetraploid.
'Gomer Waterer', which has 'Pink Pearl' as a documented pollen parent, is a
triploid.
'Graf Zeppelin', which has 'Pink Pearl' as a documented seed parent, is a
diploid.
'J.G. Millais', which has 'Pink Pearl' as a documented pollen parent, is a diploid.
'Topsvoort Pearl', which is documented sport of 'Pink Pearl', is a triploid.
'Ebony Pearl', which is documented sport of 'Pink Pearl', is a triploid.
'Mother of Pearl', which is a documented sport of 'Pink Pearl', is a diploid.
'Phyllis Korn', which has 'Gomer Waterer' as a document pollen parent, is a triploid.
'Countess of Derby', which has 'Pink Pearl' as the documented seed parent and 'Cynthia' as the documented pollen parent, is a tetraploid.
'Trude Webster', which is documented as 'Countess of Derby' selfed, is a tetraploid.
'Diane', which is documented as the seed parent of 'Phyllis Korn', is a diploid.
'Summer Peach', which has 'Phyllis Korn' as a documented pollen parent, is a diploid.
'Summer Wind' and 'Peach Recital', which have 'Summer Peach' as a documented pollen parent, are a diploids.
Seedlings of Jim Barlup's cross of 'Phyllis Korn' by 'Trude Webster' have been determined to be pentaploids.
These results from the researchers at the University of Coimbra indicate 4 generations of fertile triploids, that triploids can produce diploid, triploid, tetraploid, and pentaploid offspring, and sports of triploids can be both ploidy stable and ploidy unstable.
Summary of Ploidy Levels
Diploid 'Diane',
Diploid 'Graf Zeppelin',
Diploid 'J.G. Millais',
Diploid 'Mother of Pearl',
Diploid 'Peach Recital,
Diploid 'Summer Peach',
Diploid 'Summer Wind',
Triploid 'Broughtonii',
Triploid 'Cynthia',
Triploid 'Ebony Pearl',
Triploid 'Gomer Waterer',
Triploid 'Phyllis Korn',
Triploid 'Pink Pearl',
Triploid 'Topsvoort Pearl',
Tetraploid 'Antoon van Welie',
Tetraploid 'Countess of Derby',
Tetraploid 'Trude Webster',
Pentaploid Seedlings of 'Phyllis Korn' X 'Trude Webster'
Source: Whitney Nursery
John and Sally Perkins
