'Lady De Rothchild' is a Diploid

Rhododendron 'Lady De Rothchild', which is a 1925 Waterer hybrid documented as Rhododendron griffithianum x 'Sappho' has been determined to be a diploid using flow cytometry by

Dr. João Loureiro, Dr. Silvia Castro, José Cerca Oliveira, and Mariana Castro
Plant Ecology and Evolution Group,
Centre for Functional Ecology,
Department of Life Sciences,
Faculty of Science and Technology,
University of Coimbra, Portugal.

Summary of Ploidy Levels

Diploid 'Lady De Rothchild'

Source: Whitney Nursery

John and Sally Perkins

'Alice' is a Diploid

Rhododendron 'Alice', which is a 1910 Waterer hybrid documented as Rhododendron griffithianum hybrid has been determined to be a diploid using flow cytometry by

Dr. João Loureiro, Dr. Silvia Castro, José Cerca Oliveira, and Mariana Castro
Plant Ecology and Evolution Group,
Centre for Functional Ecology,
Department of Life Sciences,
Faculty of Science and Technology,
University of Coimbra, Portugal.

Summary of Ploidy Levels

Diploid 'Alice'

Source: Whitney Nursery

John and Sally Perkins

'Siskin' is a Tetraploid

Rhododendron 'Siskin', which is a Waterer Knaphill documented as a crossed between Rhododendron luteum and Rhododendron molle, has been determined to be a tetraploid using flow cytometry by

Dr. João Loureiro, Dr. Silvia Castro, José Cerca Oliveira, and Mariana Castro
Plant Ecology and Evolution Group,
Centre for Functional Ecology,
Department of Life Sciences,
Faculty of Science and Technology,
University of Coimbra, Portugal.

Summary of Ploidy Levels

Diploid Rhododendron molle,
Tetraploid Rhododendron luteum,
Tetraploid 'Siskin'

Source: Planeview Nursery

John and Sally Perkins

'Nancy Waterer' is a Tetraploid

Rhododendron 'Nancy Waterer', which is a 1869 Waterer Ghent hybrid, has been determined to be a tetraploid 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, Portugal.

To date, all Ghent deciduous azaleas have tested as triploid or tetraploid.

Rhododendron 'Nancy Waterer' was also determined to be a tetraploid using flow cytometry by Tom Eeckhaut.

Summary of Ploidy Levels

Triploid 'Bronze Unique',
Triploid 'Daviesii',
Triploid 'Deep Rose',
Triploid 'Gloria Mundi',
Triploid 'Josephine Klinger',
Tetraploid 'Bijou des Amateurs',
Tetraploid 'Comte de Flandre',
Tetraploid 'Heureuse Surprise',
Tetraploid 'Ignacea',
Tetraploid 'Julius Caesar',
Tetraploid 'Lelia',
Tetraploid 'Madame Gustave Guillemot',
Tetraploid 'Nancy Waterer',
Tetraploid 'Raphael de Smet'

Source: Arnold Arboretum Accession Number: 1174-53
Source: Azaleatuin
Source: George Hibben from Arnold Arboretum

John and Sally Perkins

'Toucan' is a Tetraploid

Rhododendron 'Toucan', which is a Waterer hybrid documented as a Mollis hybrid, has been determined to be a tetraploid 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, Portugal.

Rhododendron 'Toucan' is very fertile.

Rhododendron molle is a diploid species.

Summary of Ploidy Levels

Diploid Rhododendron molle,
Tetraploid 'Toucan'

Source: Arnold Arboretum Accession Number: 189-72

John and Sally Perkins

'Furnivall's Daughter' is a Diploid

Rhododendron 'Furnivall's Daughter', which is a Waterer hybrid documented as 'Mrs. Furnivall' hybrid, has been determined to be a diploid 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, Portugal.

Summary of Ploidy Levels

Diploid 'Furnivall's Daughter',
Diploid 'Mrs. Furnivall'

Source: Van Veen Nursery

John and Sally Perkins

'Madame Carvalho' is a Diploid

Rhododendron 'Madame Carvalho', which is a 1866 Waterer hybrid documented as R. catawbiense hybrid has been determined to be a diploid 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, Portugal.

Rhododendron 'Madame Carvalho' is the seed parent of 'Gomer Waterer'. 'Pink Pearl' is the pollen parent of 'Gomer Waterer'.

Summary of Ploidy Levels

Diploid 'Madame Carvalho',
Triploid 'Gomer Waterer',
Triploid 'Pink Pearl'

Source: Van Veen Nursery

John and Sally Perkins

'J.G. Millais' is a Diploid

Rhododendron 'J.G. Millais', which is a 1915 Waterer hybrid documented as 'Ascot Brilliant' x 'Pink Pearl', has been determined to be a diploid 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, Portugal.

Rhododendron 'J.G. Millais' has as ancestors 'Broughtonii' and 'Pink Pearl' which are both triploids.

Summary of Ploidy Levels

Diploid 'J.G. Millais',
Triploid 'Broughtonii',
Triploid 'Pink Pearl'

Source: Van Veen Nursery

John and Sally Perkins

'Gomer Waterer' is a Fertile Triploid

Rhododendron 'Gomer Waterer', which is a 1900 Waterer hybrid documented as 'Madame Carvalho' x 'Pink Pearl', 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, Portugal.

'Gomer Waterer', which has 'Broughtonii' and 'Pink Pearl' as ancestors, is documented as the pollen parent of 'Phyllis Korn', which has been determined to be a triploid. 'Diane', which is a diploid, is the seed parent of 'Phyllis Korn'.

'Gomer Waterer' is a 19th century hybrid hardy in zone 6.

Summary of a Polyploidy Ancestor Chain involving 'Gomer Waterer'

'Broughtonii' to 'Pink Pearl' to 'Gomer Waterer' to 'Phyllis Korn' to ('Phyllis Korn' X 'Trude Webster')

Summary of Fertile Triploids

'Anna Rose Whitney',
'Betty Wormald',
'Broughtonii',
'Cynthia',
'Cotton Candy',
'Gomer Waterer',
'Lydia',
'Platinum Pearl',
'Phyllis Korn',
'Pink Pearl',
'Rwain',
'Taurus',
'Val d'Aulnay'

Summary of Triploids from the 19th Century

'Broughtonii' 1840,
'Cynthia' 1856,
'Beauty of Littleworth' 1884,
'Pink Pearl' 1892,
'Gomer Waterer' 1900

Summary of Polyploids Hardy in Zone 6

'Anita Gehnrich',
'August Lamken',
'Cynthia',
'Gartendirektor Rieger',
'Gomer Waterer',
'Grace Seabrook',
'Hallelujah',
'Phyllis Korn',
'Solidarity',
'Taurus',
'Trude Webster'

Summary of Ploidy Levels

Diploid 'Diane',
Diploid 'Madame Carvalho',
Triploid 'Anita Gehnrich',
Triploid 'Anna Rose Whitney',
Triploid 'August Lamken',
Triploid 'Beauty of Littleworth',
triploid 'Betty Wormald',
Triploid 'Broughtonii',
Triploid 'Cotton Candy',
Triploid 'Cynthia',
Triploid 'Gartendirektor Rieger',
Triploid 'Gomer Waterer',
Triploid 'Grace Seabrook',
Triploid 'Hallelujah',
Triploid 'Lydia',
Triploid 'Phyllis Korn',
Triploid 'Pink Pearl',
Triploid 'Platinum Pearl',
Triploid 'Rwain',
Triploid 'Solidarity',
Triploid 'Taurus',
Triploid 'Val d'Aulnay',
Tetraploid 'Trude Webster',
Pentaploid (2 Seedlings from 'Phyllis Korn' X 'Trude Webster')

Source: John and Sally Perkins

John and Sally Perkins

'Lady Eleanor Cathcart' is a Diploid

Rhododendron 'Lady Eleanor Cathcart', which is a 1850 John Waterer hybrid documented as R. maximum x R. arboreum, has been determined to be a diploid 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, Portugal.

Summary of Ploidy Levels

Diploid 'Lady Eleanor Cathcart'

Source: Jane Brooks

John and Sally Perkins

'Pink Pearl' is a Fertile Triploid.

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

'Mrs. Furnivall' is a Diploid

Rhododendron 'Mrs. Furnivall', which is a H. Waterer hybrid documented as Xgriffithianum x Xcaucasicum, has been determined to be a diploid 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, Portugal.

Summary of Ploidy Levels

Diploid 'Furnivall's Daughter',
Diploid 'Mrs. Furnivall'

Source: Whitney Nursery

John and Sally Perkins

'Viscosepalum' is a Tetraploid

Rhododendron 'Viscosepalum', which is 1842 Waterer hybrid often documented to be Rhododendron molle X Rhododendron viscosum, has been determined to be a tetraploid 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, Portugal.

The Perkins' Pollen Based Ploidy Test indicated than 'Viscosepalum' was most likely a tetraploid.

Since Rhododendron molle and Rhododendron viscosum are both diploid species, the documented parentage of 'Viscosepalum' is questionable.

Rhododendron 'Daviesii', which is also documented to be Rhododendron molle X Rhododendron viscosum and was breed in the same time frame as 'Viscosepalum', has been determined using flow cytometry to be a triploid.

Summary of Ploidy Levels

Diploid Rhododendron molle,
Diploid Rhododendron viscosum,
Triploid Rhododendron 'Daviesii',
Tetraploid Rhododendron atlanticum,
Tetraploid Rhododendron 'Viscosepalum'

Source: John and Sally Perkins

John and Sally Perkins