atlanticum X caledulaceum is a Tetraploid

[Rhododendron atlanticum X Rhododendron calendulaceum] "Broken Arrow", which is a Dick Jaynes hybrid, 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

Tetraploid Rhododendron atlanticum,
Tetraploid Rhododendron calendulaceum,
Tetraploid Rhododendron atlanticum X Rhododendron calendulaceum "Broken Arrow",
Tetraploid Rhododendron atlanticum X Rhododendron calendulaceum orange,
Tetraploid Rhododendron atlanticum X Rhododendron calendulaceum pink

Source: Arnold Arboretum Accession Number: 410-2002

John and Sally Perkins

'Horizon Monarch' X 'Doreen Gale' is a Tetraploid

Seven seedlings of Rhododendron 'Horizon Monarch' X 'Doreen Gale', which were raised by Marc Colombel, have 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.

In the case of the tetraploid seedling of 'Horizon Monarch' (4X) X 'Doreen Gale' (4X), a tetraploid by a tetraploid produced a tetraploid indicating that normal meiosis most likely occurred for both tetraploid parents. In other words, the tetraploid seedlings of 'Horizon Monarch' X 'Doreen Gale' having 52 chromosomes received 26 chromosomes from the tetraploid 'Horizon Monarch' and 26 chromosomes from the tetraploid 'Doreen Gale'.

Summary of Ploidy Levels

Tetraploid 'Doreen Gale',
Tetraploid 'Horizon Monarch',
Tetraploid 7 Seedlings of 'Horizon Monarch' X 'Doreen Gale'

Source Marc Colombel

John and Sally Perkins

atlanticum X calendulaceum is a Tetraploid

2 Seedlings of [Rhododendron atlanticum X Rhododendron calendulaceum] have been determined to be 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

Tetraploid Rhododendron atlanticum,
Tetraploid Rhododendron calendulaceum,
Tetraploid Rhododendron atlanticum X Rhododendron calendulaceum "Broken Arrow",
Tetraploid Rhododendron atlanticum X Rhododendron calendulaceum orange,
Tetraploid Rhododendron atlanticum X Rhododendron calendulaceum pink

Source: George Hibben

John and Sally Perkins

'Epoch' X augustinii is a Tetraploid

Rhododendron 'Epoch' X Rhododendron augustinii, which is a Kehr hybrid, 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

Triploid 'April Rhapsody',
Triploid 'Bluenose',
Triploid 'Purple Gem',
Tetraploid 'Blue Baron',
Tetraploid 'Blue Ridge',
Tetraploid 'Epoch',
Tetraploid 'Epoch' X Rhododendron augustinii,
Tetraploid "Medium Blue",
Tetraploid Rhododendron augustinii

Source: RareFind Nursery

John and Sally Perkins

'Brigg's Red Star' x 'Point Defiance' is a Tetraploid

Two seedlings of Rhododendron 'Brigg's Red Star' x 'Point Defiance', which were raised by Ned Brockenbrough, have 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.

Summary of Ploidy Levels

Tetraploid 'Brigg's Red Star'
Tetraploid 'Point Defiance'
Tetraploid 2 Seedlings of 'Brigg's Red Star' x 'Point Defiance'

Source: Ned Brockenbrough

John and Sally Perkins

'Horizon Monarch' X 'L'Engin' is a Tetraploid

Five seedlings of Rhododendron 'Horizon Monarch' X 'L'Engin', which were raised by Marc Colombel, have 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.

In the case of the tetraploid seedling of 'Horizon Monarch' (4X) X 'L'Engin' (4X), a tetraploid by a tetraploid produced a tetraploid indicating that normal meiosis most likely occurred for both tetraploid parents. In other words, the tetraploid seedlings of 'Horizon Monarch' X 'L'Engin' having 52 chromosomes received 26 chromosomes from the tetraploid 'Horizon Monarch' and 26 chromosomes from the tetraploid 'L'Engin'.

Summary of Ploidy Levels

Tetraploid 'Horizon Monarch',
Tetraploid 5 Seedlings of 'Horizon Monarch' X 'L'Engin',
Tetraploid 'L'Engin'

Source Marc Colombel

John and Sally Perkins

'Legend' is a Tetraploid

Rhododendron 'Legend', which is a Jim Barlup hybrid documented as 'Point Defiance' x 'Lem's Monarch', 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 'Legend' has as ancestors 'Anna', 'Norman Gill', 'The Honourable Jean Marie de Montague', 'Marinus Koster', 'Point Defiance', and 'Lem's Monarch'.

In the case of the tetraploid 'Legend', a tetraploid crossed with a tetraploid produced a tetraploid indicating that normal reduced meiosis most likely occurred for both parents. In other words, 'Legend' having 52 chromosomes received 26 chromosomes from the tetraploid 'Point Defiance' and 26 chromosomes from the tetraploid 'Lem's Monarch'.

Summary of Ploidy Levels

Diploid 'Anna',
Diploid 'Norman Gill',
Diploid 'The Honourable Jean Marie de Montague',
Tetraploid 'Legend',
Tetraploid 'Lem's Monarch',
Tetraploid 'Marinus Koster',
Tetraploid 'Point Defiance'

Source: Whitney Nursery

John and Sally Perkins

'Doreen Gale' is a Tetraploid

Rhododendron 'Doreen Gale', which is a Sanders hybrid documented as 'Point Defiance' x 'Trude Webster', 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 'Doreen Gale' has as ancestors 'Anna', 'Norman Gill', 'The Honourable Jean Marie de Montague', 'Broughtonii', 'Cynthia', 'Pink Pearl', 'Marinus Koster', 'Point Defiance', 'Countess of Derby', and 'Trude Webster'.

In the case of the tetraploid 'Doreen Gale', a tetraploid crossed with a tetraploid produced a tetraploid indicating that normal reduced meiosis most likely occurred for both parents. In other words, 'Doreen Gale' having 52 chromosomes received 26 chromosomes from the tetraploid 'Point Defiance' and 26 chromosomes from the tetraploid 'Trude Webster'.

Summary of Ploidy Levels

Diploid 'Anna',
Diploid 'Norman Gill',
Diploid 'The Honourable Jean Marie de Montague',
Triploid 'Broughtonii',
Triploid 'Cynthia',
Triploid 'Pink Pearl',
Tetraploid 'Countess of Derby',
Tetraploid 'Doreen Gale',
Tetraploid 'Gorgeous George',
Tetraploid 'Marinus Koster',
Tetraploid 'Point Defiance',
Tetraploid 'Trude Webster'

Source Marc Colombel

John and Sally Perkins

'Gorgeous George' is a Tetraploid

Rhododendron 'Gorgeous George', which is a Sanders hybrid documented as 'Point Defiance' x 'Trude Webster', 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 'Gorgeous George' has as ancestors 'Anna', 'Norman Gill', 'The Honourable Jean Marie de Montague', 'Broughtonii', 'Cynthia', 'Pink Pearl', 'Marinus Koster', 'Point Defiance', 'Countess of Derby', and 'Trude Webster'.

In the case of the tetraploid 'Gorgeous George', a tetraploid crossed with a tetraploid produced a tetraploid indicating that normal reduced meiosis most likely occurred for both parents. In other words, 'Gorgeous George' having 52 chromosomes received 26 chromosomes from the tetraploid 'Point Defiance' and 26 chromosomes from the tetraploid 'Trude Webster'.

Summary of Ploidy Levels

Diploid 'Anna',
Diploid 'Norman Gill',
Diploid 'The Honourable Jean Marie de Montague',
Triploid 'Broughtonii',
Triploid 'Cynthia',
Triploid 'Pink Pearl',
Tetraploid 'Countess of Derby',
Tetraploid 'Doreen Gale',
Tetraploid 'Gorgeous George',
Tetraploid 'Marinus Koster',
Tetraploid 'Point Defiance',
Tetraploid 'Trude Webster'

Source: Whitney Nursery

John and Sally Perkins

'Trude Webster' is a Tetraploid

Rhododendron 'Trude Webster', which is a Harold Greer hybrid documented as 'Countess of Derby' X 'Countess of Derby', 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 hybridization work of Jim Barlup indicates that 'Trude Webster' is fertile in both directions when crossed with known and suspected polyploid elepidotes.

'Countess of Derby', which was determined to be a tetraploid, is the documented pollen parent of 'Anna Rose Whitney', which has been determined to be a triploid by the Coimbra based research team.

'Pink Pearl', which is the documented seed parent of 'Countess of Derby', was also determined to be a triploid by the Coimbra based research team.

'Cynthia', which is the documented pollen parent of 'Countess of Derby', was also determined to be a triploid by the Coimbra based research team.

The findings of the Coimbra based research team indicate 6 multi generational polyploid branches starting with the triploid 'Broughtonii', namely 1)'Broughtonii', 'Pink Pearl', 'Gomer Waterer', and 'Phyllis Korn', 2)'Broughtonii', 'Pink Pearl', 'Cynthia', 'Countess of Derby', and 'Anna Rose Whitney', 3)'Broughtonii', 'Pink Pearl', 'Cynthia', 'Countess of Derby', and 'Van',
4)'Broughtonii', 'Pink Pearl', 'Cynthia', 'Countess of Derby', and 'Lucky Strike',
5)'Broughtonii', 'Pink Pearl', 'Cynthia', 'Countess of Derby', 'Trude Webster', 'Platinum Pearl', and 'Gentle Giant' and 6)'Broughtonii', 'Pink Pearl', 'Antoon van Welie', 'Lydia', 'Trude Webster', and 'Grand Slam'.

Summary of Ploidy Levels

Triploid 'Anna Rose Whitney',
Triploid 'Broughtonii',
Triploid 'Cynthia',
Triploid 'Gomer Waterer',
Triploid 'Lydia',
Triploid 'Lucky Strike',
Triploid 'Pink Pearl',
Triploid 'Phyllis Korn',
Triploid 'Platinum Pearl',
Triploid 'Van',
Tetraploid 'Antoon van Welie',
Tetraploid 'Countess of Derby',
Tetraploid 'Gentle Giant',
Tetraploid 'Grand Slam',
Tetraploid 'Trude Webster'

Source: Greer Gardens
Source: Bob Fox

John and Sally Perkins

Chickasaw X Golden Comet

Here are Bruce Clyburn's seedlings of 'Chickasaw' X luteum 'Golden Comet' a cross by Sally and John Perkins.

'Chickasaw' is a "pollen sterile" tetraploid found by Clarence Towe in the wild and R. luteum 'Golden Comet' is a tetraploid selected by the Rhododendron Species Foundation.

'Chickasaw' was suspected of being a triploid but flow cytometry indicates 'Chickasaw' is a tetraploid.