'Julia Caroline' is a Triploid

Rhododendron 'Julia Caroline', which is a Ned Brockenbrough hybrid documented as 'Horizon Lakeside' x 'Point Defiance', has been determined to be a triploid 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 'Anna',
Diploid 'Horizon Lakeside',
Diploid 'Nancy Evans',
Diploid 'Norman Gill'
Diploid 'The Honourable Jean Marie de Montague',
Triploid 'Julia Caroline',
Tetraploid 'Marinus Koster',
Tetraploid 'Point Defiance'

Source: Whitney Nursery

John and Sally Perkins

[Treated 'Nancy Evans'] X 'Point Defiance' is a Tetraploid

One seedling of [Briggs chemically treated Rhododendron 'Nancy Evans'] X Rhododendron 'Point Defiance', which was raised by Ned Brockenbrough, 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.

Summary of Ploidy Levels

Diploid 'Nancy Evans'
Tetraploid 'Point Defiance'
Tetraploid 1 Seedling of [treated 'Nancy Evans'] X 'Point Defiance'

Source: Ned Brockenbrough

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 Lakeside' x 'Point Defiance' is a Tetraploid

Two seedlings of Rhododendron 'Horizon Lakeside' 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

Diploid 'Horizon Lakeside'
Tetraploid 'Point Defiance'
Tetraploid 2 Seedlings of 'Horizon Lakeside' x 'Point Defiance'

Source: Ned Brockenbrough

John and Sally Perkins

'Nancy Evans' x 'Point Defiance' is a Tetraploid

One seedling of Rhododendron 'Nancy Evans' x 'Point Defiance', which was raised by Ned Brockenbrough, 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.

Summary of Ploidy Levels

Diploid 'Nancy Evans'
Tetraploid 'Point Defiance'
Tetraploid 1 Seedling of 'Nancy Evans' x 'Point Defiance'

Source: Ned Brockenbrough

John and Sally Perkins

'Horizon Monarch' is a Tetraploid

Rhododendron 'Horizon Monarch', which is a Ned Brockenbrough hybrid documented as 'Nancy Evans' x 'Point Defiance', 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 'Horizon Monarch' has as ancestors 'Anna', 'Hotei', 'Lem's Cameo', 'Nancy Evans', 'Norman Gill', 'The Honourable Jean Marie de Montague', 'Horizon Monarch', 'Marinus Koster', and 'Point Defiance'.

In the case of the tetraploid 'Horizon Monarch', a diploid crossed with a tetraploid produced a tetraploid indicating that unreduced meiosis may have occurred for the diploid parent. In other words, 'Horizon Monarch' having 52 chromosomes received something similar to 26 chromosomes from the diploid 'Nancy Evans' and 26 chromosomes from the tetraploid 'Point Defiance'.

Rhododendron 'Horizon Monarch' was also determined to be a tetraploid using flow cytometry by Dr. Thomas Ranney, J.R. Jones, and Nathan Lynch.

Summary of Ploidy Levels

Diploid 'Anna',
Diploid 'Hotei',
Diploid 'Lem's Cameo',
Diploid 'Nancy Evans',
Diploid 'Norman Gill',
Diploid 'The Honourable Jean Marie de Montague',
Triploid 'Steredenn',
Tetraploid 'Horizon Monarch',
Tetraploid 'Marinus Koster',
Tetraploid 'Point Defiance'

Source Marc Colombel

John and Sally Perkins

'Nancy Evans' is a Diploid

Rhododendron 'Nancy Evans', which is a Ned Brockenbrough hybrid documented as 'Hotei' x 'Lem's Cameo', 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.

This Coimbra based research team also determined that 'Hotei' and 'Lem's Cameo' are diploids.

Rhododendron 'Nancy Evans' is seed fertile but pollen sterile.

'Nancy Evans' is the seed parent of 'Horizon Monarch', which was determined to be a tetraploid using flow cytometry by Dr. Thomas Ranney, J.R. Jones, and Nathan Lynch. This indicates that 'Nancy Evans' may occasionally throw unreduced gametes.

Summary of Ploidy Levels

Diploid 'Hotei',
Diploid 'Lem's Cameo',
Diploid 'Nancy Evans',
Tetraploid 'Horizon Monarch'

Source: Whitney Nursery

John and Sally Perkins

'Horizon Lakeside' is a Diploid

Rhododendron 'Horizon Lakeside', which is a Ned Brockenbrough hybrid documented as ('Nancy Evans' x 'Lem's Cameo') X 'Skipper', 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 'Horizon Lakeside',
Diploid 'Lem's Cameo',
Diploid 'Nancy Evans'

Source Marc Colombel

John and Sally Perkins

'Peach Charm' is a Diploid

Rhododendron 'Peach Charm', which is a Ned Brockenbrough hybrid documented as 'Nancy Evans' X ('Lem's Whopper' X 'Lem's Cameo'), 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 'Lem's Cameo',
Diploid 'Nancy Evans',
Diploid 'Peach Charm'

Source Marc Colombel

John and Sally Perkins