Rhododendron 'Sugar Pink', which is a Harold Greer hybrid documented as 'Trude Webster' x ('Fawn' x 'Queen o' the May Group'), 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.
'Sugar Pink' has 'Broughtonii', 'Pink Pearl', 'Cynthia', 'Countess of Derby', and 'Trude Webster' as ancestors.
Summary of Ploidy Levels
Triploid 'Broughtonii',
Triploid 'Cynthia',
Triploid 'Pink Pearl',
Triploid 'Sugar Pink',
Tetraploid 'Countess of Derby',
Tetraploid 'Trude Webster'
Source: Greer Gardens
John and Sally Perkins
